JP3358148B2 - Communication system and method and receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[Table of Contents] The present invention will be described in the following order. Industrial Application Conventional Technology (FIGS. 25 to 28) Problems to be Solved by the Invention Means for Solving the Problems Action Embodiment (1) Principle of the Present Invention (FIGS. 1 to 3) (2) Second One embodiment (FIGS. 4 to 9) (3) Second embodiment (FIG. 10) (4) Third embodiment (FIG. 11) (5) Fourth embodiment (FIG. 12) (6) Fifth embodiment (FIG. 13) (7) Sixth embodiment (FIG. 14) (8) Seventh embodiment (FIGS. 15 and 16) (9) Eighth embodiment (FIG. 17) (10) Ninth embodiment (FIG. 18) (11) Tenth embodiment (FIG. 19) (12) Other embodiments (12-1) First modification (FIGS. 20 and 21) (12-2) Second modification (FIG. 22) (12) -3) Third Modification (FIG. 23) (12-4) Fourth Modification (FIG. 24) (12-5) Fifth Modification (12-6) Sixth Modification (12-7) Seventh Modification Example (12-8) Eighth Modification Effect of the Invention

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication system, a transmitter and a receiver thereof, and a communication method therefor, and is suitably applied to, for example, a cordless telephone system for performing communication using a spread spectrum system.

[0003]

2. Description of the Related Art Conventionally, in this type of cordless telephone system, intermittent reception is generally performed on the slave unit side during standby in order to extend the battery life of the slave unit.
Here, the intermittent reception will be described with reference to FIGS. Fig As shown in 25, in the transmitter 1 of the cordless telephone system using a spread spectrum system, the data rate f _D of the information data S1 information modulation section 2
It is made to input to. The information modulating unit 2 modulates a predetermined carrier based on the input information data S1, and obtains a carrier frequency f ₀ and a bandwidth BW _D of 1 as a result.
The next modulated wave S2 is output to the multiplier 3. In this case, for example, BPSK (Binary Phase Shift K)
eying: A so-called two-phase phase shift keying (FM) modulator or FM (Fr
An equency Modulation (so-called frequency modulation) modulator is used.

The multiplier 3 receives the primary modulated waves S2 and P
The primary modulated wave S2 is subjected to spread spectrum modulation by multiplying by a PN (Pseudo Noise code) signal S3 generated by the N generator 4, and the resulting spread spectrum wave S4 is converted to a band pass filter (BPF). 5 is output. Bandpass filter 5 limits the bandwidth of the spread spectrum wave S4, which is inputted, and outputs a spread spectrum wave S5, band-limited bandwidth BW _SS. The spread-spectrum wave S5 is input to the power amplifying unit 6, where it is amplified and then radiated from the antenna 7.

On the other hand, as shown in FIG. 26, in a receiver 8 of a cordless telephone system using a spread spectrum system, a reception signal received by an antenna 9 is input to a band pass filter (BPF) 10. I have. Bandpass filter 10 the center frequency f ₀ from the received signal, extracting the spread spectrum waves S6 in bandwidth BW _SS. The extracted spread spectrum wave S6 is divided into two, one of which is supplied to the time separation control circuit 11, and the other is supplied to the multiplier 12.

The time discrimination control circuit 11 is a circuit for acquiring and maintaining synchronization, and acts on the PN generator 13 to generate a PN signal S3 in the received signal and a PN generated by the PN generator 13.
Control is performed so that the signal S7 is synchronized with the signal S7. In particular,
The time separation control circuit 11 uses the spread spectrum wave S6 and the PN
The synchronization with the PN signal S7 generated by the generator 13 is checked, and the PN generator 13 is controlled in accordance with the checked synchronization result, thereby acquiring and maintaining the synchronization. Incidentally, the time separation control circuit 11 is constituted by a sliding correlator, a delay lock loop circuit and the like.

The multiplier 12 despreads the spread spectrum wave S6 by multiplying the supplied spread spectrum wave S6 by the PN signal S7 generated by the PN generator 13, and obtains the resulting despread wave S8. To a bandpass filter (BPF) 14. Bandpass filter 14 limits the bandwidth of the despread waves S8, takes out the primary modulation wave S9 in bandwidth BW _D. The primary modulation wave S9 is transmitted to the information demodulation unit 1
5 and performs demodulation corresponding to the information modulating unit 2 to obtain information data S10.

Incidentally, when a BPSK modulator is used for the information modulation section 2, the primary modulation wave S9 is a BPSK modulation wave, so that, for example, a delay detector is used as the information demodulation section 15. When an FM modulator is used for the information modulator 2, the primary modulation wave S9 is an FM modulation wave, and therefore, for example, a frequency detector is used as the information demodulator 15.

In the receiver 8 configured as described above, during standby, intermittent reception is performed at the timing shown in FIG. That receiver 8, and the section receives the operation time T _ON, stops the interval reception operation time T _OFF. This is repeated with a period of time T _W. By the way, time T
_ON is set to, for example, about 1.2 [ms], and time _TW is set to, for example, about 3 [s].

FIG. 28 shows a reception procedure of the receiver 8 at the time of waiting. In the receiver 8, first, step SP0
And reception starts at step SP1. At this time, in step SP2, the receiver 8 sets the time T of a predetermined timer to "0". Next, in step SP3, the receiver 8 performs synchronization acquisition of the PN signal by the time separation control circuit 11. At this time, the time required from the start of the reception of the receiver 8 until the synchronization of the PN signal can be obtained is represented by T.
_Set to ₁ . When the receiver 8 acquires the synchronization of the PN signal, P
PN signal S7 synchronized with the received signal by N generator 13
Is generated, and the time separation control circuit 11
The synchronization of the signal S7 is maintained. In this case, the time discrimination control circuit 11 acquires synchronization by using a sliding correlator and maintains synchronization by using a delay lock loop circuit.

The receiver 8 proceeds to step SP4 if the synchronization of the PN signal can be obtained, and proceeds to step SP5 if the synchronization cannot be obtained. In step SP4, the receiver 8 starts demodulation by the information demodulation unit 15, and proceeds to the next step SP6 to confirm the ID (so-called identifier). In this case, the receiver 8 uses the ID included in the received signal.
The ID is confirmed by comparing with the ID of the own station,
By confirming this ID, it is known that the own station has been called. This time is T ₂ the time required until a confirmation ID from the start of demodulation. When the receiver 8 detects the calling of its own station by confirming the ID, the receiver 8 proceeds to the next step SP7 and starts the line setting.

On the other hand, if the ID cannot be confirmed in step SP6, the receiver 8 proceeds to step SP8,
Here, the timer time T is compared with the reception time T _ON, and if the timer time T is shorter, the process returns to step SP4 to repeat the processing. If the timer time T is longer, the process proceeds to step SP9. In step SP9, the receiver 8 ends the reception, and compares the repetition period T _W of the timer time T and the intermittent reception at the next step SP10. As a result, it starts receiving again Te Modotsu to step SP1 if greater than the time T is the repetition period T _W of the timer.

[0013] Further, in step SP3, when the synchronization of the PN signal cannot be obtained and the process proceeds to step SP5, the receiver 8 compares the timer time T with the reception time T _ON . As a result, if the time T of the timer is smaller, the step SP
3 and repeat the process of acquiring the synchronization.
If is larger, the process shifts to step SP9 to end the reception.

In this way, in the receiver 8, when the reception is started, the PN signal is synchronized within the reception time T _{ON due} to the absence of the received signal, weak signal strength, or interference. If acquisition is not possible, reception is terminated, and even if synchronization is acquired, ID cannot be confirmed and reception is terminated if ID is not that of the own station.
Then, the receiver 8 stops the receiving operation for the time of (T _W -T _ON ), and restarts the receiving after the lapse of the time. Therefore in the receiver 8, as the reception time T _ON, require at least synchronization acquisition sum of the time T ₁ and the ID confirmation time _{T 2 (= T 1 + T} 2) or more.

[0015]

The battery life of a cordless telephone system tends to be longer as the average power during standby is smaller. Therefore a small specific T _ON / T _W between the reception time T _ON and the repetition period T _W, yet better power consumption of the circuit is small is desirable. If the repetition period T _W is lengthened, the average power during standby decreases, but on the other hand, even if called from the base unit, the handset does not perform reception operation for the time T _W , so the drawback that calls are delayed. Occurs. Therefore, the repetition period T _W cannot be so long (substantially 3 seconds or less).

On the other hand, the reception time T _ON has the following problem. In the spread spectrum method, it is necessary to acquire synchronization of a PN signal before demodulation. In general, there are two methods for acquiring synchronization of a PN signal: a method using a sliding correlator, and a method using a match filter.
There are types.

The sliding correlator is a circuit for examining a change in the correlation value by slightly shifting the chip plate of the PN generator and the chip plate of the received signal, and searching for a peak of the correlation value. While this sliding correlator can simplify the circuit configuration and reduce power consumption,
There is a disadvantage that it takes time to acquire synchronization. That is, when a sliding correlator is used, the synchronization acquisition time T ₁ is longer, so that the reception time T _ON is longer, and as a result, there is a disadvantage that the power consumption during standby increases.

On the other hand, the match filter is configured to output the PN signal 1
A circuit that finds the leading phase of a PN signal within a period,
Although it is possible to shorten the synchronization acquisition time T _1, there is a disadvantage that power consumption is increased. That is, when a match filter is used, the reception time T _ON can be shortened, but there is a disadvantage that the power consumption is increased as a whole. Either of these methods has a common disadvantage that the average power consumption during standby cannot be reduced. This has a fundamental cause in that synchronization of the PN signal needs to be obtained.

That is, when the spread spectrum method is used, the synchronization of the PN signal must be obtained, and one more step of processing is required as compared with the non-spread spectrum method. For this reason, the spread spectrum method is disadvantageous in extending the battery life. However, even if the spread spectrum method is used, if the ID can be confirmed before the synchronization of the PN signal is obtained,
It is considered that the reception time T _ON can be shortened, the power consumption during standby can be reduced, and the battery life can be extended.

The present invention has been made in view of the above points, and proposes a communication system, a transmitter and a receiver thereof, and a communication method thereof which can reduce power consumption during standby and extend battery life. What you want to do.

[0021]

[0022]

According to the present invention, in order to solve the above-mentioned problems, a primary modulation wave modulated based on input information data is subjected to spread spectrum modulation.
In a communication system including a transmitter that transmits the resulting spread spectrum signal and a receiver that receives the spread spectrum signal transmitted from the transmitter, the transmitter includes:
Based on the information data, a predetermined modulation is performed on the carrier having the frequency f ₀ to generate a primary modulation wave, and the repetition frequency f _PN is 1
As subjected to spread spectrum modulation the larger spreading code than the bandwidth BW _D follows modulated wave in connexion the first modulation wave by the multiplying the first modulation wave, the receiver spreading code used on the transmission side when synchronization is during or synchronization to be acquired is deviated with respect to the primary modulated wave components of bandwidth BW _D is a partial bandwidth of the received spread spectrum signal one taken out, the primary modulation wave component extracted If the data is demodulated based on the information and the synchronization with the spreading code used on the transmitting side is obtained, a spreading code synchronized with the spreading code used on the transmitting side is generated and despread into the received spread spectrum signal. To demodulate the information data.

[0023]

[0024]

[Action] receiver, primary modulation wave component of the bandwidth BW _D is a partial bandwidth of the received spread spectrum signal one extraction demodulates the information data based on the first modulation wave component extracted, When synchronization with the spreading code used on the transmitting side is obtained, a spreading code synchronized with the spreading code used on the transmitting side is generated, and the received spread spectrum signal is despread to demodulate information data. I did it. By doing so, the reception time during standby can be shortened by the time required to acquire the synchronization of the spreading code as compared with the conventional case, the power consumption during standby can be reduced, and the spread used by the transmission side can be reduced. When the synchronization with the code is obtained, it is possible to switch to the reception of the normal spread spectrum system to perform good communication, and to improve the communication quality.

[0025]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

(1) Basic Configuration of the Present Invention In this section, the basic configuration of the present invention will be described. First one
The bandwidth of the primary modulation wave is BW _D , the carrier frequency of the primary modulation wave is f ₀ , the bandwidth of the spread spectrum wave is BW _SS , the repetition frequency of the PN signal used as a spreading code is f _PN ,
One cycle of the PN signal is T _PN , and the chip plate is f _CP .
Since the PN signal has a period, the frequency spectrum of the PN signal is not continuous, and as shown in FIG. 1, f _PN = 1
/ T _PN of being One spread lined with a number of carriers in the interval. However, FIG. 1 shows a case where the length of one cycle of the PN signal, that is, the number of chips n is 15.

[0027] In this case the transmission side, and a repetition frequency f _PN bandwidth BW _D and PN signal of the primary modulated wave, the following expression

(Equation 1) When the relationship is set as shown in FIG. 2, the frequency spectrum of the spread spectrum wave at that time is as shown in FIG. As shown in FIG. 2, the spectrum of the primary modulation wave bandwidth BW _D will be arranged more on the frequency axis. For example, when the primary modulation wave is a BPSK modulation wave, each of these becomes a similar BPSK modulation wave. In this case, as long as the expression (1) is satisfied, adjacent spectra do not overlap. For this reason, each spectrum of the spread spectrum wave can be separated and extracted.

By the way, when any one spectrum of the spread spectrum wave is extracted, the extracted spectrum becomes a primary modulated wave. Therefore, if the extracted spectrum is demodulated, information data can be demodulated without performing despreading. When the spread spectrum wave is multiplied by a PN signal synchronized with the transmitting side and subjected to despreading, it becomes a primary modulated wave of one spectrum. Also in this case, by demodulating the obtained primary modulated wave, information data can be demodulated.

Thus, the spread spectrum wave satisfying the expression (1) can be demodulated as a spread modulation wave or as a single primary modulation wave. Therefore, if modulation is performed on the transmitting side to satisfy the expression (1), the receiving side can select and demodulate an advantageous demodulation method according to the situation. For example, at the time of intermittent reception, if any one spectrum of the spread spectrum wave (that is, any one primary modulation wave) is extracted and demodulated, the ID can be confirmed without despreading by the PN signal, and the ID can be confirmed. It is possible to check early whether a station is called.

FIG. 3 shows the reception time T _ON in this case. As shown in FIG. 3, conventionally, the reception time T _ON is required at least for both the synchronization acquisition time T ₁ of the PN signal and the ID confirmation time T ₂ , but if the transmission is performed as described above, Any one spectrum of the spread spectrum wave can be extracted and demodulated, and the reception time T _ON can be improved only by the ID confirmation time T ₂ . Therefore, according to this method, the reception time T _ON can be shortened, and the power consumption during standby can be reduced as a whole.

FIG. 4 shows a specific example of the PN signal and information data in the transmitter. As shown in FIG.
The N signal forms one cycle with 15 chips, and the time T _{CP of} one chip is set to 0.6 [μS]. Therefore, the chip plate f _CP is given by

(Equation 2) It becomes about 1.5 [MHz] as shown in FIG.

The time T _PN of one cycle of the PN signal is about 10
[ΜS], the repetition frequency f _PN is given by the following equation:

(Equation 3) It becomes about 100 [KHz] as shown in FIG. In the transmitter, the bandwidth BW _D of the primary modulation wave output from the information modulation unit is set to the data rate f _D, and the bandwidth BW _SS of the band-pass filter provided downstream of the spread modulation unit is set to the chip plate f _CP .

Further, as shown in FIG. 4 (B), one bit of the information data when such correspond to two cycles of the PN signal, time T _D of the data 1 bit becomes 20 [μS]. Accordingly, the bandwidth BW of the primary modulation wave output from the information modulation unit
_D is the data rate f _D , and

(Equation 4) It becomes about 50 [KHz] as shown in FIG. In this way, the transmitter determines the PN signal and the information data so as to satisfy the above equation (1). Hereinafter, the transmitter and the receiver of the cordless telephone system according to each embodiment will be described assuming that the PN signal and the information data are set to the above values.

(2) First Embodiment In FIG. 5, reference numeral 20 denotes a transmitter as a whole, which inputs information data S1 at a data rate f _D to an information modulator 21. Information modulation section 21 based on the information data S1 input by modulating a predetermined carrier, and outputs the resulting carrier frequency f _0, a primary modulation wave S2 of bandwidth BW _D to spread modulation unit 22.

The spread modulation section 22 inputs the primary modulated wave S2 to the multiplier 23. The multiplier 23 generates a PN signal S1 having a repetition frequency f _PN (> BW _D ) generated by the PN generator 24.
The primary modulated wave S2 is subjected to spread spectrum modulation by multiplying by 0 and the primary modulated wave S2, and the resulting spread spectrum wave S11 is output to a band-pass filter (BPF) 25 as a filtering means. I do. Bandpass filter 25 limits the bandwidth of the spread spectrum wave S11 inputted, it outputs a spread spectrum wave S12 whose band is limited to the bandwidth BW _SS. This spread spectrum wave S
The signal 12 is input to a power amplifier 26, amplified there, and then radiated from an antenna 27.

On the other hand, in FIG. 6, reference numeral 30 denotes a receiver as a whole, and a reception signal S13 received by an antenna 31 is input to a band-pass filter (BPF) 32. The band-pass filter 32 has a center frequency of f ₀ + k · f _PN (where k is an integer) and a bandwidth of B
W _D is the filtering means, extracting one primary modulated wave by connexion optionally be extracted spectrum of a portion of the received signal S13. In this case, the center frequency of the bandpass filter 32 can be arbitrarily selected as long as it is within the band of the spread spectrum wave, and k is an arbitrary integer, and f ₀ + k · f _PN
Can be set to As is apparent from FIG. 2, since the spectrum having the highest energy is the spectrum at k = ± 1, the center frequency of the band-pass filter 32 is usually set to f ₀ + f _PN or f ₀ −f _PN. . Incidentally, in the case where it has divide there are interference waves in the band of f ₀ + f _PN or f ₀ -f _PN is the center frequency of the band pass filter 32 to a different value by setting k to another value I do.

The band-pass filter 32 outputs one primary modulated wave S14 extracted in this way to the information demodulation unit 33. The information demodulation unit 33 performs demodulation processing corresponding to the information modulation unit 21 on the transmission side on the primary modulation wave S14, and demodulates and outputs information data S10.

As described above, the receiver 30 is constituted by a receiver dedicated to a narrow band primary modulated wave which does not perform despreading. In this configuration, demodulation is performed using only a part of the energy of the received spread spectrum wave, so it cannot be said that the efficiency is high, but there is no problem in using it in a place with sufficient electric field strength, Power consumption can be reduced by not performing despreading. Because the despreading is not performed, the reception time T _ON when waiting for the synchronization acquisition time T ₁
Is shortened. As a method of using the receiver 30, a method of using it as a terminal that only knows whether or not its own station has been called during standby or as a simple receiver can be considered. Also, a terminal using a receiver that performs normal despreading may be used together with a terminal using the receiver 30,
Alternatively, if this receiver 30 and a receiver that performs normal despreading are provided and used together in one terminal, the communication quality can also be guaranteed.

By the way, the information modulating section 21 on the transmitting side has a BPS
When the K modulator is used, the primary modulation wave S14 is BPS
Since it becomes a K-modulated wave, a delay detector is used as the information demodulation unit 33, for example. In addition, the information modulator 21 is provided with FM (Fr
equency Modulation: so-called frequency modulation), FSK
(Frequency Shift Keying: so-called frequency shift keying), MSK (Minimum Shift Keying: so-called narrow band frequency shift keying), GMSK (Guassian filtered Mini)
Frequency modulation such as mum Shift Keying (so-called band-limited narrowband frequency shift keying), QPSK (Quadrature Pha
se Shift Keying: phase shift modulation such as so-called 4-phase shift keying, AM (Amplitude Modulation: so-called amplitude modulation), DSB (Double SideBand: so-called double-sideband modulation), ASK (Amplitude Shift Keying: so-called amplitude shift) When amplitude modulation such as transfer modulation is used, a demodulator (for example, a frequency detector, a phase detector, a saturation detector, etc.) corresponding to each modulation method is used as the information demodulation unit 33.

The information data S1 is binary data,
Any waveform signal such as multi-valued data or an analog signal can be used. Here, the configuration of the information modulation unit 21 in that case will be described. First, a case where binary information is used as the information data S1 and the information modulation unit 21 is configured by a BPSK modulator will be described with reference to FIG. BPSK modulator 40
Then, the information data S1 composed of binary data is input to the multiplier 41. The multiplier 41 receives the input information data S1 and a sine wave signal S2 of frequency f ₀ generated by the carrier oscillator 42.
The modulated wave S21 is output to the bandpass filter 43. Thus by limiting the bandwidth of the I connexion modulated wave S21 to bandpass filter 43 bandwidth BW _D, the carrier frequency f _0, BPSK modulated wave S22 consisting bandwidth BW _D is obtained.

A case where an analog value is used as the information data S1 and the information modulator 21 is formed of an FM modulator will be described with reference to FIG. In the FM modulator 50, information data S1 composed of an analog value is input to the low-pass filter 51. The low-pass filter 51 has an appropriate impulse response, shapes the input information data S1 into a waveform, and outputs it to the voltage-controlled oscillator 52. Voltage controlled oscillator 5
2 changes the oscillation frequency in accordance with the input information data S1, thereby obtaining the carrier frequency f ₀ and the bandwidth BW _D.
And generates an FM modulated wave S23. By the way, when the information data S1 consisting of a binary signal is inputted in this configuration, F
An SK modulated wave, an MSK modulated wave, and a GMSK modulated wave can be obtained.

Here, the receiver 30 configured as described above is used.
, The procedure shown in FIG. 9 is executed and intermittent reception is performed during standby. First, the receiver 30 enters from step SP20 and starts reception in step SP21. At this time, in step SP22, the receiver 30 sets the time T of a predetermined timer to "0". Next, in step SP23, the receiver 30 extracts any one primary modulated wave from the received signal S13 by the band pass filter 32, and demodulates the extracted primary modulated wave to the transmitting side. And demodulate the information data S10.

Then, the receiver 30 proceeds to the next step SP2.
At 4, the ID is confirmed by comparing the ID included in the received signal S13 with the ID of the own station. As a result, if the ID matches that of the own station, the receiver 3
0 indicates that the own station has been called and the next step SP2
Go to 5. In step SP25, the receiver 30
Starts the setting of the communication line by performing processing such as ringing a calling bell.

On the other hand, if the ID cannot be confirmed in step SP24, the receiver 30 proceeds to step SP26, where the timer time T is compared with the reception time T _ON . As a result, if the time T of the timer is smaller, the receiver 30 returns to step SP23 and repeats the demodulation processing. If the time T of the timer is larger, the receiver SP27.
To end the reception. The receiver 30 compares the repetition period T _W of the timer time T and the intermittent reception at the next step SP28, starts receiving again Te Modotsu to step SP21 if larger in time T of the timer.

In the above configuration, if the receiver 30 cannot detect a call addressed to the own station during the reception time T _ON , the receiver 30 stops the reception operation, and after that, when the time (T _W −T _ON ) elapses, the receiver 30 is restarted. Start receiving. At this time, the receiver 30
Since despreading is not performed as in the related art, the reception time T _ON is shortened by the synchronization acquisition time T ₁ of the PN signal, and the power consumption during standby can be reduced.

In the conventional receiver 8, assuming that 60 cycles of the PN signal are required for synchronization acquisition and 30 data bits are required for ID confirmation, the synchronization acquisition time T ₁ is 0.6 [ms] and the ID confirmation time T ₂ is 0.6. [Ms], the reception time T _ON (= T ₁ +
T ₂ ) requires 1.2 [ms]. However, in the case of this embodiment, since no despreading is performed, the synchronization acquisition time T ₁ becomes unnecessary, and the reception time T _ON (= T ₂ )
0.6 [ms], which is better in half of the conventional case. Therefore, in the case of this embodiment, if the simple calculation is performed only in the standby mode, the battery life is doubled.

[0047] Thus in the case of this embodiment, the primary modulation wave S2 of bandwidth BW _D, a PN signal S10 consisting in the bandwidth BW greater repetition frequency f _PN than _D (> BW _D) using spread and transmit the primary modulation wave bandwidth BW _D is a partial band within the band of the spread spectrum wave S13 received one taken out to demodulate the reception side. As a result, the receiver 30 can confirm the calling of its own station before the synchronization of the PN signal is obtained, and the reception time can be shortened by the time required for the synchronization to reduce the power consumption during standby. .

[0048] According to the above configuration per nuclei, in the transmitting side, spectrum spread modulation using a PN signal S10 consisting of a frequency f _PN (> BW _D) Repeat primary modulation wave S2 of bandwidth BW _D so as to transmit Te, the reception side, by which the primary modulation wave bandwidth BW _D of spread spectrum waves S13 received so as to demodulate one taken out, the power consumption during the waiting time of the receiver 30 And the battery life can be extended.

(3) Second Embodiment In FIG. 10, in which parts corresponding to those in FIG. 6 are assigned the same reference numerals, reference numeral 60 denotes a receiver according to the second embodiment as a whole.
Three band-pass filters 61A to 61 as filtering means
The configuration is almost the same as that of the receiver 30 shown in FIG. 6 except that C is provided. However, in the case of this embodiment,
The transmitter is the same as the transmitter 20 shown in FIG.

Received signal S13 received by antenna 31
Is input to the band-pass filter 61A, 61B or 61C by the switching switch 62A. Each of the band pass filters 61A to 61C is for extracting one arbitrary primary modulated wave from the received signal S13.
Bandwidth bandpass filter 61A is set to BW _D, the center frequency is set to f ₀ -f _PN, center frequency extracting primary modulation wave of f ₀ -f _PN. The band-pass filter 61B bandwidth is set to BW _D, the center frequency is set to f _0, the center frequency is f ₀ 1
Extract the next modulated wave. The band-pass filter 61C bandwidth is set to BW _D, the center frequency is set to f ₀ + f _PN, center frequency extracting primary modulation wave of f ₀ + f _PN.

The primary modulated wave S14 extracted by the band-pass filters 61A to 61C is input to the information demodulation unit 33 via the switching switch 62B, where the information is subjected to demodulation processing corresponding to the transmission side. Demodulated in S10.

By the way, the switching switches 62A, 62B
Are switched synchronously, for example, the switching switch 62A
Is switched to the bandpass filter 61A side, the switching switch 62B also switches to the bandpass filter 61A side. At this time, the switching switches 62A, 62
Switching of B is performed by manual operation of the holder or by a control signal supplied from the outside.

As described above, in the case of the second embodiment, three band-pass filters 61A to 61C having different center frequencies are used instead of the band-pass filter 32 having a variable center frequency used in the first embodiment. Is provided, and the band pass filter to be used is switched according to the situation such as an interference wave. This switches the extracted primary modulated wave,
The best primary modulated wave can be extracted and received.
Incidentally, also in this embodiment, in order to perform demodulation on the extracted first modulation wave, there is no need for the despreading, waiting to shorten the synchronization amount corresponding receive time T _ON of the acquisition time T ₁ of the PN signal Power consumption at the time can be reduced.

According to the above configuration, three band-pass filters 61A to 61 having different center frequencies are provided.
By providing C and switching according to the situation such as an interfering wave, the best primary modulated wave can be extracted and received, and a good communication state can be ensured.
Also, since demodulation is performed on the extracted primary modulated wave, P
By shortening the reception time T _ON by the synchronization acquisition time T ₁ of the N signal, the power consumption during standby can be reduced, and the battery life of the receiver 60 can be prolonged.

(4) Third Embodiment In FIG. 11, in which parts corresponding to those in FIG. 10 are assigned the same reference numerals, 65 is a receiver according to the third embodiment as a whole, and a communication quality measuring unit 66 is provided. Except for this, the configuration is almost the same as that of the receiver 60 shown in FIG.

The primary modulation wave S14 extracted by the bandpass filter 61A, 61B or 61C is input to the communication quality measuring section 66, and the information data S10 demodulated by the information demodulating section 33 is input. The communication quality measuring unit 66 receives the input primary modulated wave S14 and information data S
10 to judge whether the reception state such as the signal level or the data error rate is good or not, and outputs a switching control signal S30 in accordance with the result of the determination to switch the switching switches 62A and 62B.
Switch. As a result, in the receiver 65, a band-pass filter (61A) used in accordance with the situation such as an interfering wave is used.
To 61C), and the primary modulated wave to be extracted can be switched to extract and receive the best primary modulated wave.

Incidentally, the communication quality measuring section 66 only needs to be able to measure parameters for determining a signal level, a data error rate, and the like. For example, the eye pattern aperture ratio of the primary modulated wave S14 and the information data S10 and the like can be measured. , The signal-to-interference ratio C / I may be measured. Also in this embodiment, since demodulation is performed on the extracted primary modulated wave, there is no need for despreading, and the synchronization acquisition time T _{1 of the} PN signal is obtained.
And the power consumption during standby can be reduced by shortening the reception time T _ON .

According to the above configuration, the reception state is determined by the communication quality measuring section 66, and the bandpass filters (61A to 61C) are switched according to the determination result. The primary modulated wave can be extracted and received, and a good communication state can be ensured. In addition, since demodulation is performed on the extracted primary modulated wave, the reception time T _ON can be shortened by the synchronization acquisition time T ₁ of the PN signal, thereby reducing the power consumption during standby. The life of the 60 batteries can be extended.

(5) Fourth Embodiment In FIG. 12, in which parts corresponding to those in FIG. 11 are assigned the same reference numerals, 70 denotes a receiver according to the fourth embodiment as a whole. In the case of this embodiment, By performing frequency conversion, one band-pass filter (BPF) 71 is the best one.
The next modulated wave is extracted and received.

More specifically, first, the reception signal S13 received by the antenna 31 is input to a bandpass filter (BPF) 72 as a filtering means. Bandpass filter 72
Has a bandwidth set to BW _SS , a center frequency set to f ₀ , extracts only a spread spectrum wave from the received signal S13, and extracts the extracted spread spectrum wave S3
1 is output to the multiplier 73. The multiplier 73 performs frequency conversion on the spread spectrum wave S31 by multiplying the input spread spectrum wave S31 by the oscillation signal S32 generated by the sine wave oscillator 74, and obtains the resulting frequency-converted spectrum. The spread wave S33 is output to a bandpass filter 71 as a filtering means.

The band pass filter 71 has a bandwidth BW _D
, The center frequency is set to f ₀ , and only one primary modulation wave having a center frequency of f ₀ is extracted from the frequency-spread spectrum spread waves S33, and the extracted primary modulation wave S34 is extracted. Output to the information demodulation unit 33. The information demodulation unit 33 demodulates the information data S10 by performing demodulation processing corresponding to the transmission side on the input primary modulated wave S34.

The communication quality measuring section 66 has a primary modulated wave S34.
And information data S10. The communication quality measuring unit 66 determines the reception state based on the primary modulation wave S34 and the information data S10, and changes the oscillation frequency of the oscillation signal S32 generated by the sine wave oscillator 74 according to the determination result. As a result, the best primary modulated wave can be frequency-converted to the center frequency f ₀ , and the best primary modulated wave can be extracted by the band-pass filter 71 and received in the best condition (that is, changing the oscillation frequency). Accordingly, the primary modulation wave extracted by the bandpass filter 71 can be switched.)

More specifically, the sine wave oscillator 74 generates an oscillation signal S32 having an oscillation frequency of k · f _PN (where k ≧ 0), and the communication quality measuring section 66 calculates the value of k. Change. For example, when k = 1, the oscillation frequency of the oscillation signal S32 becomes _fPN . Therefore, the primary modulated wave converted to the center frequency f ₀ has the center frequency f ₀
+ F _PN and f ₀ -f _PN are two primary modulated waves. That is, the synthesis of the two primary modulation waves is frequency-converted to the center frequency f ₀ .

Incidentally, here, k = 0 is the oscillation signal S32.
Is a DC component, and means that frequency conversion is not performed. As can be seen from FIG. 2, k = 1, at which the signal-to-noise ratio S / N becomes maximum if there is no interference wave.
Is usually optimal. Also, when k = 1 and k = −1
Since the frequency is the same as in the case of, it is sufficient to perform only for k ≧ 0. Also in the case of this embodiment, since the demodulated primary modulated wave is demodulated, there is no need for despreading, and the reception time T _ON is equivalent to the synchronization acquisition time T ₁ of the PN signal.
And the power consumption during standby can be reduced.

According to the above configuration, the multiplier 73 and the sine wave oscillator 74 are provided as frequency conversion means, and the received spread spectrum wave S31 is subjected to frequency conversion using the frequency conversion means. By controlling the frequency conversion means according to the reception state, the best primary modulated wave can be extracted and received, and a good communication state can be secured. In addition, since demodulation is performed on the extracted primary modulated wave, the reception time T _ON can be shortened by the synchronization acquisition time T ₁ of the PN signal, thereby reducing the power consumption during standby. 70 battery life can be prolonged.

(6) Fifth Embodiment In FIG. 13, in which parts corresponding to those in FIG. 12 are assigned the same reference numerals, reference numeral 75 denotes a receiver according to the fifth embodiment as a whole. By converting the spread spectrum wave into a base band, a low-pass filter (LPF) 76 extracts and receives the best primary modulated wave.

More specifically, first, the reception signal S13 received by the antenna 31 is input to the bandpass filter 72,
Here, only the spread spectrum wave S31 is extracted.
This spread spectrum wave S31 is input to the multiplier 73. The multiplier 73 receives the input spread spectrum wave S31.
Is multiplied by the oscillation signal S35 generated by the sine wave oscillator 77 to perform frequency conversion on the spread spectrum wave S31, and outputs the frequency-converted spread spectrum wave S36 obtained as a result to the low-pass filter 76.

The cut-off frequency of the low-pass filter 76 is set to BW _D / 2, and only one primary modulated wave converted to the base band is extracted from the frequency-spread spectrum spread wave S36 and extracted. The primary modulation wave S37 is output to the information demodulation unit 33. The information demodulation unit 33 demodulates the information data S10 by performing demodulation processing corresponding to the transmission side on the input primary modulated wave S37.

Here, in the sine wave oscillator 77, an oscillation signal S having an oscillation frequency of f ₀ + k · f _PN (where k is an integer)
35 is generated. Therefore, the spread spectrum wave 31
If the value of k is set in advance so that the primary modulated wave that can be received well is converted to the baseband, the best primary modulated wave can be extracted and received. As is clear from FIG. 2, the optimum is usually obtained when k = ± 1 at which the signal-to-noise ratio S / N is maximized when there is no interference wave. For example, when k = 1 and an oscillation signal S35 having an oscillation frequency of f ₀ + f _PN is generated, the primary modulation wave converted to the baseband is a primary modulation wave having a center frequency of f ₀ + f _PN. . Incidentally, in the case of this embodiment as well, since demodulation is performed on the extracted primary modulated wave, there is no need for despreading, and the reception time T _ON is shortened by the synchronization acquisition time T ₁ of the PN signal. Power consumption during standby can be reduced.

According to the above arrangement, the multiplier 73 and the sine-wave oscillator 77 are provided as frequency conversion means, and the frequency of the spread spectrum wave S36 frequency-converted by the frequency conversion means is shifted to the base band. Low-pass filter 7 for extracting the converted primary modulated wave
6, the best primary modulated wave can be extracted and received, and a good communication state can be ensured. In addition, since demodulation is performed on the extracted primary modulated wave, the reception time T _ON can be shortened by the synchronization acquisition time T ₁ of the PN signal, thereby reducing the power consumption during standby. 75 battery life can be extended.

(7) Sixth Embodiment In FIG. 14, in which parts corresponding to those in FIG. 13 are assigned the same reference numerals, reference numeral 78 denotes a receiver according to the sixth embodiment as a whole. The configuration is substantially the same as that of the receiver 75 shown in FIG. 13 except that the oscillation frequency of the sine wave oscillator 77 is controlled.

Specifically, the primary modulation wave S37 and the information data S10 are input to the communication quality measuring section 79,
The communication quality measuring unit 79 calculates the input primary modulated wave S37.
The reception state is determined based on the information signal S10 and the oscillation signal S generated by the sine wave oscillator 77 according to the determination result.
The oscillation frequency of 35 is changed. In this case, the sine wave oscillator 77 generates an oscillation signal S 35 having an oscillation frequency of f ₀ + k · f _PN (where k is an integer), and the communication quality measuring section 79 changes the value of k. As a result, the best primary modulated wave of the spread spectrum wave S31 can be frequency-converted to baseband, and the best primary modulated wave can be extracted by the low-pass filter 76 and received in the best condition ( That is, by changing the oscillation frequency, the primary modulation wave extracted by the low-pass filter 76 can be switched.

According to the above configuration, the communication quality measuring section 79 for changing the oscillation frequency of the sine wave oscillator 77 according to the reception state is provided, so that the best primary wave of the spread spectrum wave S31 is obtained. A modulated wave can be extracted and received, and a good communication state can be ensured.

(8) Seventh Embodiment In FIG. 15, reference numeral 80 denotes a receiver according to the seventh embodiment as a whole, which is characterized in that it comprises two means for demodulating received signals. Specifically, first, the antenna 31
Is received by a band-pass filter (BPF) 72 as filtering means. Bandpass filter 72 bandwidth is set to BW _SS, the center frequency is set to f _0, extracting only spread spectrum waves in the received signal S13, and outputs a spread spectrum wave S31 taken out thereof. The outputted spread spectrum wave S31 is divided into two, one of which is input to the first demodulation unit 81 and the other is input to the second demodulation unit 82.

In the first demodulation section 81, first, the input spread spectrum wave S31 is input to a band pass filter (BPF) 83 as a filtering means. Bandpass filter 83 bandwidth is set to BW _D, the center frequency f ₀ + k · f _PN (where, k is an integer) is set to, Yotsute to retrieve the spectrum of a portion of the spread spectrum wave S31 An arbitrary primary modulation wave is extracted, and the extracted primary modulation wave S40 is output to the information demodulation unit 84.

Incidentally, since the center frequency of the bandpass filter 83 is set to f ₀ + k · f _PN , the center frequency can be changed by changing the value of k.
Any primary modulated wave can be extracted. Also, as is clear from FIG. 2, if there is no interference wave, the signal-to-noise ratio S /
Normally, k = ± 1 at which N is maximized is optimal. The information demodulation unit 84 performs demodulation processing corresponding to the transmission side on the input primary modulated wave S40, thereby obtaining information data S1.
0A is demodulated, and the information data S10A is output to the switching switch 85.

On the other hand, in the second demodulation section 82, the input spread spectrum wave S31 is input to the multiplier 86 and the time discrimination control circuit 87. The time separation control circuit 87 is a circuit responsible for acquiring and maintaining synchronization.
It acts on the PN generator 88 and the PN signal and PN in the received signal.
The control is performed so that the PN signal S42 generated by the generator 88 is kept in synchronization. Specifically, the time discrimination control circuit 87 uses the PN signal in the spread spectrum wave S31 and the PN generator 88
The synchronization with the PN signal S42 generated in step (1) is checked, and the PN generator 88 is controlled in accordance with the checked synchronization result, thereby obtaining and maintaining synchronization. Incidentally, the time discrimination control circuit 87 is constituted by a sliding correlator, a delay lock loop circuit and the like.

The multiplier 86 despreads the spread spectrum wave S31 by multiplying the spread spectrum wave S31 by the PN signal S42 generated by the PN generator 88, and outputs the resulting despread wave S43. The signal is output to a band-pass filter (BPF) 89 as a filtering means. Bandwidth bandpass filter 89 is set to BW _D, the center frequency is set to f _0, output from the despreading wave S43 by extracting first modulation wave S44 to information demodulation section 90.
The information demodulation unit 90 performs demodulation processing corresponding to the transmission side on the input primary modulated wave S44 to demodulate the information data S10B, and outputs the information data S10B to the switch 85.

The switching switch 85 switches according to predetermined switching conditions, and the information data S10A, S10B
And outputs it. Specifically, the switching switch 85 switches to the first demodulation unit 81 first, and after the time separation control circuit 87 acquires the synchronization of the PN signal S42, the switching switch 85 switches to the second demodulation unit 82 which can receive signals satisfactorily. Switch. In such a case, the switching may be performed according to, for example, the synchronization acquisition result of the PN signal S42 in the time separation control circuit 87. That is, when the time separation control circuit 87 detects the acquisition of the synchronization of the PN signal S42, the switching switch 85 is switched to the second demodulation unit 82 side,
The switching switch 85 may be switched to the first demodulation unit 81 until the synchronization of the signal S42 can be obtained or when the synchronization is lost.

By the way, also in the case of this embodiment, when a BPSK modulator is used for the information modulator on the transmitting side, for example, a delay detector is used for the information demodulators 84 and 90, and the FM modulator is used for the information modulator. When a demodulator is used, the information demodulators 84 and 90
For example, a frequency detector is used.

Here, the receiver 80 configured as described above actually receives and executes a procedure as shown in FIG. First, the receiver 80 enters from step SP30 and starts reception at step SP31. At this time, in step SP32, the receiver 80 sets the time T of a predetermined timer to "0". Here, in the receiver 80, the receiving procedure also branches into two paths in accordance with the presence of the two demodulating means (81, 82). That is, in the receiver 80, after step SP32, one of the receivers proceeds to step SP33,
The other shifts to step SP34.

At step SP 33, the receiver 80 uses the band-pass filter 83 to transmit the spread spectrum wave S.
An arbitrary one of the primary modulated waves in 31 is extracted, and a demodulation process corresponding to the transmitting side is performed on the extracted primary modulated wave to demodulate the information data S10A. And receiver 8
0 is the received signal S13 in the next step SP35.
The ID is confirmed by comparing the ID included therein with the ID of the own station. As a result, if the ID matches that of the own station, the receiver 80 determines that the own station has been called and proceeds to the next communication line setting procedure, and if not, proceeds to step SP36. I do.

At step SP36, the receiver 80 compares the timer time T with the reception time T _ON . As a result, if the time T of the timer is smaller, the receiver 80 proceeds to step S.
Returning to P33, the demodulation process is repeated, and if the time T of the timer is larger, the process shifts to step SP37 to end the reception. Then, the receiver 80 compares the timer time T with the intermittent reception repetition period T _{W in the} next step SP38,
If the time T of the timer becomes longer, the process returns to step SP31 to start receiving again.

On the other hand, step SP34 which is the second route
, The receiver 80 performs synchronization acquisition of the PN signal by the time separation control circuit 87. When the receiver 80 obtains the synchronization of the PN signal, the PN generator 88 generates a PN signal S42 synchronized with the received signal S13 by the PN generator 88, and
The synchronization of the PN signal S42 is maintained by the time separation control circuit 87. In this case, the time discrimination control circuit 87 obtains synchronization by using, for example, a sliding correlator, and maintains synchronization by using a delay lock loop circuit.

When the synchronization of the PN signal can be obtained, the receiver 80 exits from step SP34 and proceeds to step SP39. In step SP39, the receiver 80 performs demodulation by the information demodulation unit 90, and proceeds to the next step SP40 to confirm the ID. In this case, the receiver 80 confirms the ID by comparing the ID included in the received signal S13 with the ID of the own station. As a result, if the IDs do not match, the receiver 80 returns to step SP34 and repeats synchronization acquisition. If the IDs match, the receiver 80 proceeds to the communication line setting procedure.

Here, if the ID can be confirmed on the first route side (that is, if the ID can be confirmed at step SP35), the process proceeds to step SP41 to set the communication line. If the synchronization of the PN signal can be obtained on the path side (that is, if the result is affirmative in step SP40 and exit), the communication path is set by entering the step SP41 from the second path side. That is, until the synchronization of the PN signal can be obtained, the demodulation unit 81 performs demodulation to set the communication line, and when the synchronization of the PN signal can be obtained, the demodulation unit 82 performs demodulation to set the communication line. Incidentally, if the synchronization of the PN signal cannot be obtained or the synchronization is lost due to the influence of the interference wave or the like, the demodulation is continued on the first path side (that is, the demodulation unit 81 side).

In the above configuration, the receiver 80 has two demodulation units 81 and 82 as demodulation means, and the two demodulation units 81 and 82 perform demodulation. That is, in the receiver 80, the spread spectrum wave S
The demodulation unit 82 extracts and demodulates any one of the primary modulated waves S40, and performs despreading on the spread spectrum wave S31 by the demodulation unit 82.
3 is demodulated. By doing so, in the receiver 80, the information data S demodulated by the demodulation unit 81 is output.
ID confirmation can be performed first from 10A, and if synchronization can be obtained by the demodulation unit 82, the demodulation unit 8
2, the information data S10 in a good quality state demodulated by
It can be switched to B. Therefore, in the receiver 80, the reception time T _{ON is} equivalent to the synchronization acquisition time T ₁ of the PN signal.
To reduce standby power consumption, extend battery life, and improve communication quality by switching to normal spread spectrum reception after acquisition of PN signal synchronization. Can be.

As described above, in the receiver 80, two demodulation units, ie, a demodulation unit 81 that extracts and demodulates any one primary modulation wave from the spread spectrum wave S31 and a demodulation unit 82 of a normal spread spectrum system are used. By preparing
Two methods can be selected and demodulated. Thus, in addition to the interference immunity characteristic of the spread spectrum method, interference immunity by the frequency diversity method is provided, so that a good communication state can be ensured and communication quality can be improved.

Normally, when a narrow-band interference wave is received, if the intensity of the interference wave exceeds the desired spread spectrum wave intensity by a factor of spread gain, reception becomes impossible due to the influence of the interference wave. However, in the case of this embodiment, the demodulation unit 81, which is a narrow-band demodulation unit, extracts and demodulates only a portion of the spread spectrum wave where there is no narrow-band interference wave (that is, the frequency diversity system). Receiving the signal), it is less susceptible to interference waves. In this case, the received power is reduced, but the power of the interfering wave is further reduced, so that the signal-to-interference ratio C / I is improved.

By the way, such a receiver 80 has the ISM
(Industrial Scientific Medical) band,
This is particularly effective in an environment where it is not known what kind of radio signal is to appear at which frequency, bandwidth, and intensity.

According to the above configuration, there are provided two demodulating means: a demodulating section 81 for extracting and demodulating an arbitrary primary modulated wave from the spread spectrum wave S31 and a demodulating section 82 of a normal spread spectrum system. With this configuration, the ID can be confirmed first from the information data S10A demodulated by the demodulation unit 81, and the demodulation unit 82
Thus, if synchronization can be obtained, the signal can be demodulated by switching to the normal spread spectrum system. As a result, the reception time T _ON can be shortened, the power consumption during standby can be reduced, the battery life can be prolonged, and after the synchronization of the PN signal is acquired, the reception is switched to the normal spread spectrum reception to improve the communication quality. Can be improved.

(9) Eighth Embodiment In FIG. 17, reference numeral 95 denotes a receiver as a whole according to the eighth embodiment, which performs frequency conversion on a received spread spectrum wave and demodulates the received signal, and also performs processing on the spread spectrum wave. To perform despreading and demodulate. That is, in this embodiment, a normal spread spectrum demodulation means is added to the receiver 70 of the fourth embodiment shown in FIG.

More specifically, first, a received signal S13 received by the antenna 31 is input to a band-pass filter (BPF) 72 as a filtering means. Bandpass filter 72 bandwidth is set to BW _SS, center frequency f
_It is set to ₀ , and extracts only the spread spectrum wave from the received signal S13 and outputs the extracted spread spectrum wave S31. The output spread spectrum wave S31 is divided into two, one of which is input to the multiplier 86,
The other is input to the time separation control circuit 87.

Here, first, the switching switch 96 is switched to the sine wave oscillator 74 side. Thereby, the multiplier 8
6 multiplies the spread spectrum wave S31 by an oscillation signal S32 having an oscillation frequency of k · f _PN (where k is an integer) generated by the sine wave oscillator 74, thereby performing frequency conversion on the spread spectrum wave S31. Then, the resulting frequency-spread spectrum-spread wave S33 is output to a band-pass filter 89 as filtering means.

The bandpass filter 89 has a bandwidth BW _D
It is set to, and the center frequency is set to f _0, of the spread spectrum wave S33 whose frequency is converted, the center frequency is extracted primary modulation wave of f _0, extracted Part 1
The next modulated wave S34 is output to the information demodulation unit 90. The information demodulation unit 90 demodulates the primary modulated wave S34 to obtain the information data S
10 is output. The receiver 95 confirms the ID based on the obtained information data S10, and detects the calling of the own station.

In parallel with this, the time separation control circuit 87 acquires the synchronization of the PN signal S42 generated by the PN generator 88 based on the input spread spectrum wave S31.
As a result, when synchronization of the PN signal S42 is obtained, the receiver 95 switches the switching switch 96 to the PN generator 88 side. Accordingly, the multiplier 86 despreads the spread spectrum wave S31 by multiplying the spread spectrum wave S31 by the PN signal S42, and outputs the resulting despread wave S43 to the bandpass filter 89. The bandpass filter 89 extracts the primary modulation wave S44 from the despread wave S43, and the information demodulation unit 90 demodulates the extracted primary modulation wave S44 and outputs information data S10.

In this way, the receiver 95 uses the sine wave oscillator 74 and the multiplier 86 to generate the spread spectrum wave S3.
1 is subjected to frequency conversion, and one primary modulation wave is extracted from the frequency-converted spread spectrum wave S33 and demodulated to confirm the ID before synchronization of the PN signal is obtained. As a result, in the receiver 95, the reception time T _ON can be shortened as compared with the related art, the power consumption during standby can be reduced, and the battery life can be extended.

In the receiver 95, the time discrimination control circuit 87 acquires the synchronization of the PN signal in parallel. As a result, when synchronization can be obtained, the switch 96 is switched to perform despreading on the spread spectrum wave S31 and demodulate. As a result, the receiver 95 can switch the reception to the normal spread spectrum system after the synchronization of the PN signal is obtained, thereby improving the communication quality.

According to the above configuration, the demodulation means (74, 8) performs frequency conversion on the spread spectrum wave S31, extracts one arbitrary primary modulated wave, and demodulates the same.
6, 89, 90), a demodulating means (87, 88) for demodulating the spread spectrum wave S31 in the normal spread spectrum system, and a switching switch 96 for switching between the two demodulating means. By
In standby mode, the reception time T _ON can be shortened to extend the life of the battery, and the communication quality can be improved by switching to the reception of the normal spread spectrum system after the synchronization of the PN signal is obtained.

Incidentally, also in this embodiment, a communication quality measuring section for judging the reception state is provided similarly to the receiver 70 of the fourth embodiment shown in FIG. The oscillation frequency of the wave oscillator 74 may be changed.

(10) Ninth Embodiment In FIG. 18, reference numeral 100 denotes a receiver according to a ninth embodiment as a whole, which performs frequency conversion to a base band on a received spread spectrum wave, demodulates the received signal, and demodulates the spectrum. The spread wave is subjected to despreading, and the resulting despread wave is also subjected to frequency conversion to baseband and demodulated. That is, in this embodiment, a normal spread spectrum demodulation means is added to the receiver 75 of the fifth embodiment shown in FIG. More specifically, the spread spectrum wave S31 obtained via the antenna 31 and the bandpass filter 72 is divided into two, one of which is input to the switching switch 101, and the other of which is input to the multiplier 86 and the time separation control circuit 87. Is done.

Here, first, the switching switch 101
Is switched to the output side of the bandpass filter 72 which is the first path. As a result, the spread spectrum wave S31 is input to the multiplier 73. The multiplier 73 multiplies the input spread-spectrum wave S31 by an oscillation signal S35 having an oscillation frequency of f ₀ + k · f _PN (where k is an integer) generated by the sine wave oscillator 77 to obtain the spectrum. The spread wave S31 is subjected to frequency conversion into baseband, and the resulting spread spectrum wave S36 is output to the low-pass filter 76. Lowpass filter 76
Has a cut-off frequency set to BW _D / 2, and extracts only the primary modulated wave converted to the baseband from the frequency-spread spectrum spread wave S36. The information demodulation unit 90 demodulates the extracted primary modulated wave S37 and outputs information data S10. The receiver 100 confirms the ID based on the obtained information data S10,
Detects calling of own station.

In parallel with this, the time discrimination control circuit 87 acquires the synchronization of the PN signal S42 generated by the PN generator 88 based on the input spread spectrum wave S31.
As a result, when the synchronization of the PN signal S42 can be obtained, the receiver 100 switches the switching switch 101 to the multiplier 86 side. Thus, the despread wave S43 obtained by multiplying the spread spectrum wave S31 and the PN signal S42 by the multiplier 86 is input to the multiplier 73.

The multiplier 73 multiplies the input despread wave S43 by the oscillation signal S35 generated by the sine wave oscillator 77 to convert the frequency of the despread wave S43 into baseband. The resulting frequency-converted despread wave S50 is output to the low-pass filter 76. The low-pass filter 76 has a frequency-converted despread wave S50.
The primary demodulation wave S51 is extracted from the data, and the information demodulation unit 90 demodulates the extracted primary modulation wave S51 and outputs information data S10.

As described above, the receiver 100 uses the sine wave oscillator 77 and the multiplier 73 to generate the spread spectrum wave S
31 is subjected to frequency conversion, and one of the frequency-converted spread spectrum waves S36 converted to the baseband.
By extracting and demodulating only the next modulated wave S37,
The ID is confirmed before the synchronization of the PN signal is obtained. As a result, in the receiver 100, the reception time T _ON can be shortened as compared with the related art, the power consumption during standby can be reduced, and the battery life can be extended.

In the receiver 100, the synchronization of the PN signal is acquired by the time discrimination control circuit 87 in parallel. As a result, when synchronization can be obtained, the switching switch 101 is switched to perform despreading on the spread spectrum wave S31 and demodulate. As a result, the receiver 100 can switch to the normal spread spectrum reception after the synchronization of the PN signal is obtained, thereby improving the communication quality.

According to the above configuration, the frequency conversion is performed on the spread spectrum wave S31, and only the primary modulated wave S37 converted into the base band is extracted from the frequency converted spread spectrum wave S36 and demodulated. Demodulating means (73, 76, 77, 90) for performing despreading on the spread spectrum wave S31, and demodulating means (86 to 88) for performing frequency conversion and demodulation of the resulting despread wave S43 to baseband. ) And a switching switch 101 for switching between the two demodulation means, so that the reception time T _ON can be shortened during standby and the battery life can be prolonged. The communication quality can be improved by switching to the normal spread spectrum reception.

Incidentally, also in the case of this embodiment, a communication quality measuring section for judging the receiving state is provided similarly to the receiver 78 of the sixth embodiment shown in FIG. The oscillation frequency of the wave oscillator 77 may be changed.

(11) Tenth Embodiment In FIG. 19, reference numeral 105 denotes a receiver according to the tenth embodiment as a whole, and the position of the frequency conversion means (73, 77) of the receiver 100 shown in FIG. 18 is changed. Things.

More specifically, the spread spectrum wave S 31 obtained via the antenna 31 and the band pass filter 72 is input to the multiplier 73. The multiplier 73 multiplies the input spread spectrum wave S31 by an oscillation signal S35 generated by the sine wave oscillator 77 and having an oscillation frequency of f ₀ + k · f _PN (where k is an integer), thereby obtaining the spread spectrum. The wave S31 is subjected to frequency conversion to baseband, and the resulting spread spectrum wave S
55 is output to a low-pass filter 106 as a filtering means. The low-pass filter 106 has a cut-off frequency of f
_It is set to _CP / 2, and only the spread spectrum wave component is extracted from the spread spectrum wave S55 converted to the baseband, and the resulting spread spectrum wave S56 is obtained.
Are divided into two paths, that is, a switching switch 107, a multiplier 86, and a time separation control circuit 87, and are output.

Here, first, the switching switch 107
Is switched to the output side of the low-pass filter 106, which is the first path. As a result, the spread spectrum wave S56 is input to the low-pass filter 76. The low-pass filter 76 has a cut-off frequency set to BW _D / 2, and extracts only the primary modulated wave converted to the baseband from the spread spectrum wave S56. The information demodulation unit 90 demodulates the extracted primary modulated wave S37 and outputs information data S10. The receiver 105 confirms the ID based on the obtained information data S10 and detects the call of the own station.

In parallel with this, the time separation control circuit 87 acquires the synchronization of the PN signal S42 generated by the PN generator 88 based on the input spread spectrum wave S56.
As a result, when synchronization of the PN signal S42 is obtained, the receiver 105 switches the switching switch 107 to the multiplier 86 side. Thus, the despread wave S57 obtained by multiplying the spread spectrum wave S56 and the PN signal S42 by the multiplier 86 is input to the low-pass filter 76. The low-pass filter 76 extracts the primary modulated wave S51 from the despread wave S57, and the information demodulation unit 90 demodulates the extracted primary modulated wave S51 and outputs information data S10.

Thus, the receiver 105 uses the sine wave oscillator 77 and the multiplier 73 to generate the spread spectrum wave S.
31 is subjected to frequency conversion, and one of the frequency-converted spread spectrum waves S55,
By extracting and demodulating only the next modulated wave S37,
The ID is confirmed before the synchronization of the PN signal is obtained. As a result, in the receiver 105, the reception time T _ON can be shortened as compared with the related art, the power consumption during standby can be reduced, and the battery life can be extended.

In the receiver 105, the synchronization of the PN signal is acquired by the time discrimination control circuit 87 in parallel with this, and when the synchronization is acquired, the switching switch 107 is switched to demodulate the despread wave S57. As a result, the receiver 105 can switch to the normal spread spectrum reception after the synchronization of the PN signal is obtained, thereby improving the communication quality.

According to the above configuration, the spread spectrum wave S31 is frequency-converted, and only the primary modulated wave S37 converted to the baseband is extracted from the frequency-converted spread spectrum wave S55 and demodulated. Demodulation means (73, 77, 76, 90, 106)
A demodulation means (86-88) for despreading and demodulating the frequency-spread spectrum spread wave S55 and a switching switch 107 for switching the two demodulation means are provided. T _ON can be shortened to extend the life of the battery, and after synchronization of the PN signal is obtained, communication can be improved by switching to normal spread spectrum reception.

Incidentally, also in the case of this embodiment, a communication quality measuring section for judging the reception state is provided similarly to the receiver 78 of the sixth embodiment shown in FIG. The oscillation frequency of the wave oscillator 77 may be changed.

(12) Other Embodiments (12-1) First Modification In the seventh embodiment, the switching switch 8
Although the case where 5 is provided after the information demodulation units 84 and 90 has been described, the present invention is not limited to this, and the switching switch 85 may be provided before the information demodulation unit 111 as shown in FIG. The same effect as in the above case can be obtained. In this case, the configuration can be further simplified by reducing the number of the information demodulation units by one. Incidentally, in this case, since the center frequencies of the signals (S40, S44) output from the bandpass filters 83, 89 are different (specifically, f ₀ + k · f _PN and f ₀ ), the information demodulation unit 11
1 needs to be able to handle both.

Further, the present invention is not limited to this modification, and as shown in FIG. 21, even if the bandpass filters 116 to 118 are switched, the same effect as in the above case can be obtained. In this case, the band-pass filter, the center frequency and the band pass filter 116 of f ₀ + f _PN, the bandpass filter 117 of center frequency f _0, 3 of the center frequency f ₀ -f _PN bandpass filter 118 There are types. There are two types of switching switches, a switching switch 119 for demodulation switching and a switching switch 120A, 120B for filter switching.

The switching switch 119 can be switched on the basis of synchronization acquisition of the PN signal, similarly to the switching switch 85 of the seventh embodiment. On the other hand, the switching switch 120
The switching conditions for A and 120B are as follows.
When there is no interfering wave during standby, the center frequency is f ₀
+ F _PN bandpass filter 116 or center frequency is f
_The switching switches 120A and 120B are switched so as to select the _0- f _PN bandpass filter 118. If there is an interfering wave during standby, the signal-to-interference ratio C /
The switching switches 120A and 120B are switched so that the primary modulation wave with the best I can be extracted. Check the ID in response to the call, if the synchronization of the PN signal could be earned, it switched center frequency switch 120A switched to choose a band-pass filter 117 of f _0, the 120B.

Incidentally, also in this case, a communication quality measuring unit for judging the receiving state is provided similarly to the receiver 65 of the third embodiment shown in FIG. 11, and the switching switch 120A is used by the communication quality measuring unit. 120B may be switched. Further, here, the case where the center frequencies of the three band-pass filters are set to f ₀ + f _PN , f ₀ , and f ₀ −f _PN has been described. However, the present invention is not limited to this.
The center frequencies of the two bandpass filters are set to f ₀ +
k · f _PN (where k is an integer) may be set so that the center frequency can be changed by changing the value of k. By doing so, the best primary modulated wave can be extracted and demodulated according to the reception state.

(12-2) Second Modification In the above-described seventh embodiment, the case where the bandpass filter on the demodulation section 81 side is not switched has been described. However, the present invention is not limited to this, and FIG. As shown in the figure, the demodulation unit 81 has the center frequencies f ₀ + f _PN , f ₀ , f
_{Even if} three band-pass filters 126 to 128 of _0- f _PN are provided and these three band-pass filters 126 to 128 are switched by the switches 129A and 129B, the same effect as in the above-described case can be obtained. it can.

Incidentally, also in this case, similarly to the receiver 65 of the third embodiment shown in FIG. 11, a communication quality measuring section for judging the receiving state is provided, and the switching switch 129A, 129B may be switched. Further, here, the case where the center frequencies of the three band-pass filters are set to f ₀ + f _PN , f ₀ , and f ₀ −f _PN has been described. However, the present invention is not limited to this.
The center frequencies of the two bandpass filters are set to f ₀ +
k · f _PN (where k is an integer) may be set so that the center frequency can be changed by changing the value of k. By doing so, the best primary modulated wave can be extracted and demodulated according to the reception state.

(12-3) Third Modification In the above eighth embodiment, the switching switch 9
6 (S32, S4)
Although the case of switching 2) has been described, the present invention is not limited to this, and as shown in FIG.
Even if a switching switch 96 is provided on the input side of No. 9 to switch the signals (S33, S43) input to the bandpass filter 89, the same effect as in the above case can be obtained. Incidentally, also in this case, the fourth signal shown in FIG.
As in the receiver 70 of the embodiment, a communication quality measuring unit for judging the receiving state may be provided, and the oscillation frequency of the sine wave oscillator 74 may be changed by the communication quality measuring unit.

(12-4) Fourth Modification In the tenth embodiment described above, a band-pass filter 72 is provided between the antenna 31 and the multiplier 73, and a low-pass filter 106 is provided on the output side of the multiplier 73. However, the present invention is not limited to this. As shown in FIG. 24, a comb filter 136 is provided between the antenna 31 and the multiplier 73, and the comb filter 137 is provided on the output side of the multiplier 73. It may be provided. In this way, it is possible to remove only noise (that is, an interference wave) present in the valley of the spectrum and extract a signal component, thereby improving a signal-to-interference ratio C / I and improving anti-jamming characteristics. Incidentally, the comb filters 136 and 137 are S
This is realized by an AW filter or a digital filter. Also in this modification, as shown in FIG.
A communication quality measuring unit 138 for determining the reception state may be provided, and the communication quality measuring unit 138 may change the oscillation frequency of the sine wave oscillator 77. In the same manner, the bandpass filter 72 shown in the eighth to ninth embodiments and the bandpass filter 72 shown in the first modification to the third modification can be converted into a comb filter. can get.

(12-5) Fifth Modification In the above-described second and third embodiments, the center frequencies of the three bandpass filters are respectively set to f ₀ + f _PN and f
₀ , f ₀ −f _PN has been described, but the present invention is not limited to this, and the center frequencies of the three band-pass filters are set to f ₀ + k · f _PN (where k is an integer). , K may be changed to change the center frequency. By doing so, the best primary modulated wave can be extracted and demodulated according to the reception state. The number of bandpass filters is not limited to three, but may be other numbers.

(12-6) Sixth Modification In the above-described embodiment and the above-described modification, the case where the characteristics of the band-pass filter and the low-pass filter of the receiver are fixed has been described. However, the present invention is not limited to this. Even if the characteristics of the band-pass filter and the low-pass filter of the receiver can be changed by an external control signal, the same effects as those described above can be obtained.

(12-7) Seventh Modification In the above-described embodiment, the case where the spread spectrum wave is frequency-converted to the frequency f ₀ or the base band has been described. However, the present invention is not limited to this, and the present invention is not limited to this. In the case where the frequency conversion is performed, the same effect as in the above case can be obtained. If the local oscillation frequency is f _LO ,
In a sine wave oscillator, an oscillation signal having an oscillation frequency of f _LO + k · f _PN may be generated. In this case, the filtering means for extracting the primary modulation wave sets the center frequency to f ₀ + f _LO or f
₀ Set -f _LO or f _LO -f _0, the bandwidth may be set to BW _D.

(12-8) Eighth Modification In the above-described embodiment, the case where the present invention is applied to the transmitter and the receiver of the cordless telephone system has been described. However, the present invention is not limited to this. It can be widely applied to communication systems.

[0129]

[0130]

Effects of the Invention According to the present invention as described above, at the receiver, one primary modulation wave component of the bandwidth BW _D is a partial bandwidth of the received spread spectrum signal extraction,
Information data is demodulated based on the extracted primary modulated wave component,
When synchronization with the spreading code used on the transmitting side is obtained, a spreading code synchronized with the spreading code used on the transmitting side is generated, and the received spread spectrum signal is despread to demodulate information data. I did it. By doing so, it is possible to shorten the reception time during standby by the time required to acquire the synchronization of the spreading code as compared with the related art, reduce the power consumption during standby and extend the battery life, When synchronization with the spread code used on the transmission side can be obtained, it is possible to switch to the reception of the normal spread spectrum system to perform good communication and improve communication quality.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a spectrum of a PN signal for explaining the principle of the present invention.

FIG. 2 is a schematic diagram illustrating a spectrum of a spread spectrum wave used for explaining the principle of the present invention.

FIG. 3 is a schematic diagram showing a comparison of a reception time with the related art.

FIG. 4 is a schematic diagram illustrating a relationship between a PN signal and information data.

FIG. 5 is a block diagram showing a configuration of a transmitter according to the first embodiment.

FIG. 6 is a block diagram showing a configuration of a receiver according to the first embodiment.

FIG. 7 is a block diagram showing a configuration in the case where a BPSK modulator is used for an information modulation section.

FIG. 8 is a block diagram showing a configuration in a case where an FM modulator is used for an information modulator.

FIG. 9 is a flowchart showing a receiving procedure of the receiver according to the first embodiment.

FIG. 10 is a block diagram showing a configuration of a receiver according to a second embodiment.

FIG. 11 is a block diagram showing a configuration of a receiver according to a third embodiment.

FIG. 12 is a block diagram showing a configuration of a receiver according to a fourth embodiment.

FIG. 13 is a block diagram showing a configuration of a receiver according to a fifth embodiment.

FIG. 14 is a block diagram showing a configuration of a receiver according to a sixth embodiment.

FIG. 15 is a block diagram showing a configuration of a receiver according to a seventh embodiment.

FIG. 16 is a flowchart showing a receiving procedure of the receiver according to the seventh embodiment.

FIG. 17 is a block diagram showing a configuration of a receiver according to an eighth embodiment.

FIG. 18 is a block diagram showing a configuration of a receiver according to a ninth embodiment.

FIG. 19 is a block diagram showing a configuration of a receiver according to a tenth embodiment.

FIG. 20 is a block diagram showing a configuration of a receiver according to another embodiment.

FIG. 21 is a block diagram showing a configuration of a receiver according to another embodiment.

FIG. 22 is a block diagram showing a configuration of a receiver according to another embodiment.

FIG. 23 is a block diagram showing a configuration of a receiver according to another embodiment.

FIG. 24 is a block diagram showing a configuration of a receiver according to another embodiment.

FIG. 25 is a block diagram showing a configuration of a conventional transmitter.

FIG. 26 is a block diagram showing a configuration of a conventional receiver.

FIG. 27 is a schematic diagram showing intermittent reception timing of a conventional receiver at the time of standby.

FIG. 28 is a flowchart showing a receiving procedure of a conventional receiver.

[Explanation of symbols]

1, 20 ... transmitter, 2, 21 ... information modulator, 5, 1
0, 14, 25, 32, 43, 61A to 61C, 71,
72, 83, 89, 116 to 118, 126 to 128 ...
… Band pass filter, 8, 30, 60, 65, 70,
75, 78, 80, 95, 100, 105, 110, 1
15, 125, 130, 135 ... Receiver, 11, 87
... Time sorting control circuit, 15, 33, 84, 90, 11
1 Information demodulators, 51, 76, 106 Low-pass filters 62A-62B, 85, 101, 107, 11
9, 120A to 120B, 129A to 129B ... switch, 66, 79 ... communication quality measuring unit, 81,
82 demodulation sections, 136, 137 ... comb filters.

Claims (14)

(57) [Claims] 1. A transmitter for performing spread spectrum modulation on a primary modulation wave modulated based on input information data and transmitting a resulting spread spectrum signal, and a spread spectrum signal transmitted from the transmitter. In a communication system including a receiver for receiving a signal, the transmitter performs predetermined modulation on a carrier having a frequency f ₀ based on the information data to generate and output a primary modulation wave. by frequency f _PN multiplies the large spreading codes than the bandwidth BW _D of the first modulation wave to the primary modulated wave, comprising a spread modulation means for performing spread spectrum modulation on the first modulation wave, the receiver, one is taken out filtering means a primary modulation wave component of the bandwidth BW _D is a partial band of the spread spectrum signal received, by connexion up to the filtering means And a first demodulating means comprising at the information demodulating means for demodulating said information data based on the first modulation wave component, generates a spreading code synchronized with the spreading code used on the transmission side,
A second demodulation means for despreading the received spread spectrum signal and demodulating the information data by using the spread code, until synchronization with the spread code used on the transmission side can be obtained or synchronization is obtained. If it comes off, the first
And demodulation by the second demodulation means when the synchronization is obtained. Wherein when the k are arbitrary integers, said filtering means is a center frequency f ₀ + k · f _PN, bandwidth comprises a plurality of bandpass filters for BW _D, switching the bandpass filter communication system according to claim 1, switching the first modulation wave component, characterized in that they were taken out the best of the first modulation wave component is taken out by. 3. The communication apparatus according to claim 1, further comprising: a communication quality measuring unit configured to determine whether a reception state is good or not based on the primary modulated wave component and / or the demodulated information data. 3. The communication system according to claim 2 , wherein the bandpass filter is switched over. 4. The receiver according to claim 1, further comprising frequency conversion means for performing frequency conversion on the received spread spectrum signal, and performing frequency conversion on the spread spectrum signal by the frequency conversion means. switching the first modulation wave component retrieving Te cowpea, communication system according to claim 1, characterized in that they were taken out the best of the first modulation wave component. 5. When k is an arbitrary integer and f _LO is a local oscillation frequency, the frequency conversion means is arranged so that the oscillation frequency is k · f _PN or f ₀ + k · f _PN or f _LO + k
An oscillator for generating an oscillating signal of f _PN , and a multiplier for multiplying the spread spectrum signal and the oscillating signal, and by changing the value of k, the primary modulation extracted by the filtering means. The communication system according to claim 4 , wherein the wave components are switched. 6. When the oscillation means uses an oscillation signal having an oscillation frequency of k · f _PN , the filtering means extracts the primary modulated wave component whose center frequency is converted to f _0, and When an oscillation signal of f ₀ + k · f _PN is used, the above-mentioned primary modulated wave component frequency-converted to baseband is extracted, and an oscillation signal of an oscillation frequency of f _LO + k · f _PN is used. _Has a center frequency of f ₀ + f _LO or f ₀ −f _LO or f _LO
Communication system according to claim 5, characterized in that retrieving the frequency converted the first modulation wave component -f _0. 7. A communication quality measuring means for judging the reception quality based on the primary modulated wave component and / or the demodulated information data, wherein the communication quality measuring means responds to the judgment result of the communication quality measuring means. 6. The communication system according to claim 5 , wherein the value of k is changed. 8. A communication system according to claim 1, characterized in that it comprises a comb filter the receiver to extract only the signal components by removing the noise from the spread-spectrum signal received in the valley of the spectrum. 9. The communication system according to claim 1 , wherein said filtering means can change characteristics based on a control signal inputted from outside. 10. A primary modulated wave obtained by subjecting a carrier having a frequency f ₀ to predetermined modulation based on input information data, wherein a repetition frequency f _PN has a bandwidth BW of the primary modulated wave.
Receiving a spread spectrum signal obtained by multiplying a larger spreading codes than _D, at the receiver for demodulating the information data, primary modulation bandwidth BW _D is a partial band of said received spread spectrum signal A first demodulating means comprising filtering means for extracting one wave component, information demodulating means for demodulating the information data based on the primary modulated wave component extracted by the filtering means, Generate a spreading code synchronized with the spreading code
A second demodulation means for despreading the received spread spectrum signal and demodulating the information data by using the spread code, until synchronization with the spread code used on the transmission side can be obtained or synchronization is obtained. If it comes off, the first
A receiver characterized in that demodulation is performed by the demodulation means, and when synchronization is obtained, demodulation is performed by the second demodulation means. 11. If the k are arbitrary integers, said filtering means is a center frequency f ₀ + k · f _PN, bandwidth comprises a plurality of bandpass filters for BW _D, switching the bandpass filter 11. The receiver according to claim 10 , wherein the primary modulation wave component to be extracted is switched to thereby extract the best primary modulation wave component. 12. A frequency conversion means for performing frequency conversion on the received spread spectrum signal, wherein the frequency conversion means performs frequency conversion on the spread spectrum signal, and the frequency conversion means extracts the signal by the filtering means.
11. The receiver according to claim 10 , wherein the next modulated wave component is switched to take out the best primary modulated wave component. 13. The receiver according to claim 10 , further comprising a comb filter for removing noise existing in a valley of a spectrum from the received spread spectrum signal and extracting only a signal component. 14. A transmitter for performing spread spectrum modulation on a primary modulation wave modulated based on input information data, and transmitting a resulting spread spectrum signal, and a spread spectrum signal transmitted from the transmitter. In a communication method for a communication system including a receiver for receiving a signal, the transmitter performs predetermined modulation on a carrier having a frequency f ₀ based on the information data to generate a primary modulation wave, and generates a repetition frequency f _PN is subjected to spread spectrum modulation by connexion the first modulation wave by multiplying the large spreading codes than the bandwidth BW _D of the first modulation wave to the primary modulated wave, the receiver, the received the the primary modulation wave component of the bandwidth BW _D is a partial band of the spread spectrum signal one taken out, the information data is demodulated based on the first modulation wave component extracted, transmitted When the synchronization with the spreading code used in step (c) is obtained, a spreading code synchronized with the spreading code used on the transmitting side is generated, and the received spread spectrum signal is subjected to despreading to demodulate the information data. A communication method, comprising: