JP2940583B2 - Wireless transceiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio transceiver.
In particular, the present invention relates to a wireless transmission / reception device suitable for a communication system in which a received signal level fluctuates, such as a mobile communication system.

[0002]

2. Description of the Related Art In mobile communications, the position of a mobile station is not fixed, so that the level of a received signal is constantly fluctuating. If the received signal level becomes excessive as a result of this fluctuation, the receiving device will be saturated, causing noise and adversely affecting communication. In order to avoid this problem, there has been conventionally known a method of inserting an attenuator into a transmitting device or a receiving device.

[0003]

However, in such a method in which the attenuator is always inserted, the received signal level becomes too low depending on the conditions, and as a result, the S / N is reduced and normal communication is difficult. There is a problem that the following may occur.

[0004] The present invention solves such a problem, and can prevent saturation of the receiving apparatus when the received signal level becomes excessive, and further, prevents the received signal level from becoming excessively low. The purpose is to provide.

[0005]

Means for Solving the Problems To achieve the above object,
Therefore, the wireless transmitting and receiving apparatus according to the present invention comprises a transmitting apparatus and a receiving apparatus.
Becomes et placed, to the receiving apparatus side, and amplifying means for amplifying a received signal, and selecting means for retrieving a selectively receive and a signal which is not amplified and the amplified signal by the amplification means, of the received signal level detecting means for detecting the level, Ru and control means for controlling such that the level detecting means by the detected received signal level to select the unamplified signal by amplifying means selection means if it becomes excessive.

[0006] Another wireless transmission / reception apparatus according to the present invention.
Is composed of a transmitting device and a receiving device, and includes, on the transmitting device side, an amplifying unit for amplifying a transmission signal, and a selection unit for selectively extracting a signal amplified by the amplifying unit and a signal not amplified as a transmission output. Means, and control means for controlling the selection means to select a signal which is not amplified by the amplification means when notified that the received signal level detected by the level detection means of the partner receiving apparatus has become excessive. with Ru.

[0007] In the control means,
Also has upper and lower threshold levels, and when the received signal level detected by the level detector in the state where the upper threshold is set is equal to or higher than the upper threshold, the selection is performed. The received signal level detected by the level detecting means in the state where the threshold level is changed to the lower threshold level and the threshold level is set to the lower threshold level while controlling so that the signal not amplified by the amplifying means is selected. When the value becomes equal to or less than the lower threshold level, the selection means is controlled to select the signal amplified by the amplification means, and the threshold level is changed to the upper threshold level. .

[0008]

As described above, according to the present invention, when the reception signal level detected on the receiving device side becomes excessive ,
If the received signal level falls below the upper threshold level , a signal that does not pass through the amplifying means for amplifying the received signal in the receiving device is selected as a reception input, or the reception device determines that the reception level has become excessive. By notifying the transmission side and selecting a signal that does not pass through the amplifying means for amplifying the transmission signal in the partner transmission apparatus as a transmission output, saturation of the reception apparatus can be prevented. Furthermore, either normally selects a signal through the amplifier means for amplifying the received signal in the receiver as a reception input, or transmit output signals through the amplifier means for amplifying a transmission signal in the destination transmission apparatus selecting either as, or by selecting the signal through the amplifier means both receiving apparatus, transmitting apparatus, received signal level of the receiving device can be avoided from becoming excessively small. Further, when the received signal level detected by the level detection means is between the upper limit side and the lower limit side threshold level, since the selection means is not switched,
It is possible to avoid instability of the receiving operation and generation of switch noise due to frequent switching of the selecting means due to a slight change in the received signal level.

Further, usually, a signal passed through amplifying means for amplifying a received signal in a receiving apparatus is selected as a receiving input, or a signal passed through an amplifying means for amplifying a transmitted signal in a partner transmitting apparatus is selected. By selecting the signal as the transmission output or selecting the signal that has passed through the amplifying means for both the receiving device and the transmitting device, it is possible to prevent the received signal level of the receiving device from becoming too low.

[0010]

FIG. 1 is a block diagram showing a configuration of a receiving apparatus according to an embodiment of the present invention. This receiving apparatus includes an antenna 11, a low noise amplifier (LNA) 12, a reception input switch 13, a first mixer 14, a frequency synthesizer 15,
Band pass filter (BPF) 16, amplifier 17, second
Mixer 18, local oscillator 19, low-pass filter (LP
F) 20, a demodulator 21, a data regenerator 22, a level detector 23, and a CPU 24.

The low noise amplifier 12 amplifies a signal received by the antenna 11. The switch 13 is connected to the CPU 2
4, one of the received signal from the antenna 11 and the output signal of the low noise amplifier 12 is selected and guided to the first mixer 14. The first mixer 14
The output signal of the switch 13 is multiplied by the carrier signal from the frequency synthesizer 15 and converted to a first intermediate frequency. The band pass filter 16 extracts a desired frequency component from the output signal of the first mixer 14. Bandpass filter 1
The output signal of No. 6 is input to the second mixer 18 after being amplified by the amplifier 17. The second mixer 18 multiplies the output signal of the amplifier 17 by a local oscillation signal from the local oscillator 19 and converts the output signal to a second intermediate frequency. Low-pass filter 20
Extracts a desired frequency component from the output signal of the second mixer 18. After the output signal of the low-pass filter 20 is demodulated by the demodulator 21, it is input to the data regenerator 22, where the data is reproduced.

The output signal of the second mixer 18 is also input to the level detector 23. The level detector 23 detects a reception signal level from the output signal of the second mixer 18 and inputs a level detection output to the CPU 24. The CPU 24 captures the level detection output of the level detector 23, compares the received signal level L with a predetermined threshold level T, and controls the switch 13 according to the comparison result.

In this embodiment, the threshold level T has two threshold levels Th and Tl on the upper limit side and the lower limit side, and these are selectively set. Also, the switch 13
In the state in which the output signal of the antenna 11 is selected, the received signal level L detected by the level detector 23 does not exceed the upper threshold level Th, and the switch 13 selects the output signal of the low noise amplifier 12. In this state, the magnitudes of Th and Tl are determined so that the received signal level L does not fall below the lower threshold level Tl.

Next, the operation of this embodiment will be described with reference to the flowchart shown in FIG.

During communication between the receiving apparatus of FIG. 1 and a transmitting apparatus (not shown), the CPU 24 determines whether the set threshold level T is the upper threshold level Th or the lower threshold level Tl (S11). ).

Here, if the upper threshold level Th is set, the magnitude relationship between the received signal level L detected by the level detector 23 and the upper threshold level Th is checked (S12). If <Th, the communication is continued. L
If ≧ Th, the switch 13 is switched from the low noise amplifier 12 to the antenna 11 under the control of the CPU 24 (S13). As a result, a signal that is not amplified by the low-noise amplifier 12 is input to the switch 13 and thereafter, so that saturation of the receiving device due to excessive input can be prevented. After the switch 13 is switched to the antenna 11 side, the threshold level T is changed to the lower threshold level Tl (S14).

On the other hand, if the lower threshold level Tl is set, the magnitude relationship between the received signal level L detected by the level detector 23 and the lower threshold level Tl is checked (S15), and L> In the case of Tl, communication is continued. L ≦
In the case of Tl, the switch 13 is switched from the antenna 11 side to the low noise amplifier 12 side under the control of the CPU 24 (S16). As a result, since the signal amplified by the low noise amplifier 12 is input to the switch 13 and subsequent switches, it is possible to avoid a decrease in S / N due to an under input. After the switch 13 is switched to the low noise amplifier 12 in this way, the threshold level T is changed to the upper threshold level Th (S17).

As described above, according to the present embodiment, the more appropriate level of the signal amplified by the low noise amplifier 12 and the signal not amplified according to the received signal level detected by the level detector 23. By selecting one of the signals as the reception input by the switch 13 under the control of the CPU 24, it is possible to prevent the saturation of the receiving device and the reduction of the S / N.

In this embodiment, the upper and lower threshold levels Th and Tl are determined so that the switch 13 is not switched when the detected received signal level is between the two threshold levels Th and Tl. ing. Accordingly, it is possible to avoid instability of the receiving operation due to frequent switching of the switch 13 due to a slight change in the received signal level, and occurrence of switching noise.

In the above-described embodiment, the detection of the reception signal level in the receiving apparatus is performed at the second intermediate frequency stage. However, the reception signal level may be detected at another location.

Next, another embodiment of the present invention will be described. FIG. 3 is a block diagram illustrating a configuration of a transmission device according to another embodiment of the present invention. The transmitting device includes a modulator 31, a first mixer 32, a local oscillator 33, a band-pass filter (BPF) 34, an amplifier 35, a second mixer 36, a frequency synthesizer 37, a band-pass filter 38, a power amplifier (PA) 39, A transmission output switch 40, an antenna 41 and a CPU 42 are provided.

First, input data to be transmitted is a modulator 31.
, And is input to the first mixer 32. The first mixer 32 multiplies an output signal of the modulator 31 by a local oscillation output from the local oscillator 33 and converts the signal into a first intermediate frequency. The output signal of the first mixer 32 is input to the second mixer 36 after being amplified by the amplifier 35. Second mixer 36
Multiplies the output signal of the amplifier 35 by the carrier signal from the frequency synthesizer 37 and converts it to a second intermediate frequency.
The band-pass filter extracts a desired frequency component from the output signal of the second mixer. The output signal of the band-pass filter 38 is split into two, one of which is directly
The other is input to the switch 40 via the power amplifier 39. The switch 40 selects one of the output signal of the high-pass filter 38 and the output signal of the power amplifier 39 under the control of the CPU 42 and supplies the signal to the antenna 41 as a transmission output.

In this embodiment, a receiving device (not shown) is configured in the same manner as in FIG. If the wireless communication device of the present invention is used as the communication partner wireless device, and if the own receiving device detects an excessive signal level, the wireless communication device notifies the other party of the level control information 43 using a wireless signal. 43 is input to the CPU 42. The CPU 42 controls the switch 40 based on the level control information 43.

FIG. 4 shows a sequence of the level control information 43. When the detection of the excessively low signal level or the excessively low signal level is performed in the own receiving apparatus of FIG. 1, the level control information 43 indicating the fact is transmitted to the partner radio. The signal is transmitted to the apparatus by a radio signal, and is transmitted to the transmitting apparatus in FIG. In the partner transmitting device, the switch 42 is switched by the CPU 42 and the threshold level is changed by the CPU 24 of the receiving device in accordance with the level control information 43. That is, CPU
42 takes in the level control information 43 to know the magnitude relationship between the received signal level and the threshold level on the receiving device side,
The switch 40 is controlled based on this.

Also in the present embodiment, in the own receiving apparatus of FIG. 1, the CPU 24 has two threshold levels Th and Tl on the upper and lower sides as threshold levels T in the CPU 24, and these are selectively set.

Next, the operation of this embodiment will be described with reference to the flowchart shown in FIG.

During communication in which both the receiving apparatus shown in FIG. 1 and the transmitting / receiving apparatus shown in FIG. 3 are used, the CPU 24 of the own receiving apparatus shown in FIG. Threshold level Th or lower threshold level T
1 is determined (S21).

Here, when the upper threshold level Th is set, the CPU 24 of the own receiver in FIG. 1 determines the difference between the received signal level L detected by the level detector 23 and the upper threshold level Th. Investigate the magnitude relationship (S22), L
If <Th, the communication is continued. If L ≧ Th, the level control information 43 is sent to the partner wireless device (S
23).

The partner CPU 42 receiving the level control information 43 switches the switch 40 from the power amplifier 39 to the band-pass filter 38 (S24). As a result, a signal that is not amplified by the power amplifier 39 is transmitted from the switch 40 to the antenna 41 as a transmission output.
Therefore, on the own receiving apparatus side, saturation due to excessive input is prevented. After the switch 40 of the partner wireless device in FIG. 3 is thus switched to the band-pass filter 38 side, the CPU 24 of the own receiving device in FIG. 1 changes the threshold level T to the lower threshold value Tl (S25). ).

On the other hand, when the upper threshold level Tl is set, the CPU 24 of the own receiving apparatus in FIG. 1 determines whether the received signal level L detected by the level detector 23 is lower than the lower threshold level Tl. The relationship is examined (S26), and L>
In the case of Tl, communication is continued. When L ≦ T1,
The level control information 43 is sent to the partner wireless device (S2
7).

Upon receiving the level control information 43, the other CPU 42 sets the switch 40 to the band-pass filter 38.
Is switched to the power amplifier 39 side (S28). As a result, the signal amplified by the power amplifier 39 is transmitted from the switch 40 to the antenna 41 as a transmission output. Therefore, a decrease in S / N due to an excessive input on the own receiving apparatus side is avoided. In the CPU 24 of the own receiving apparatus in FIG.
After the switch 40 of the partner transmission device in FIG. 3 is switched to the power amplifier 39 side in this way, the threshold level T is changed to the upper threshold level Th (S29).

As described above, according to the present embodiment, according to the received signal level detected by the level detector 13 on the own receiving apparatus side in FIG. 1, the signal is amplified by the power amplifier 39 in the partner transmitting apparatus in FIG. By selecting the signal having the appropriate level from the received signal and the signal not amplified as the transmission output by the switch 40 under the control of the CPU 42, it is possible to prevent the saturation of the receiving apparatus and the decrease in S / N. .

Also in the present embodiment, the upper and lower threshold levels Th and Tl are determined, and when the received signal level is between the two threshold levels Th and Tl, the switch 40 of the partner radio apparatus is set. By preventing the switching, it is possible to avoid instability of the receiving operation due to frequent switching of the switch 40 of the partner transmitting device due to slight fluctuation of the received signal level, and occurrence of switching noise.

In the above embodiment, the level control information based on the magnitude relationship between the received signal level detected from the own receiving apparatus in FIG. 1 and the threshold level is sent to the other party transmitting apparatus in FIG. Only the information on the received signal level detected from the side may be sent to the partner transmitting apparatus side, and the transmitting apparatus may compare the magnitude relationship with the threshold level. Further, the CPU may be the same on the transmitting side and the receiving side.

[0035]

As described above, according to the present invention, the level of the received signal detected by the own receiving apparatus and the upper limit and lower
Depending on the relationship with the threshold level on the receiving side, the appropriate signal is selected from among the signals that have passed through the amplifier for amplifying the received signal and the signals that are not passed in the own receiving apparatus as the receiving input, or the detected receiving signal By notifying the other party of the level information and selecting an appropriate signal as a transmission output between a signal that has passed through an amplifier for amplifying a transmission signal and a signal that does not pass in the other party's transmitting apparatus, the excessive input of the own receiving apparatus You can kick avoid a decrease in S / N due to saturation or under-input by. In addition, the received signal level is
The selection means is switched if the
Selected by slight fluctuation of received signal level
Instability of receiving operation due to frequent switching of means
And switch noise can be avoided. Therefore, stable communication can be performed even in a communication system in which the received signal level fluctuates, such as mobile communication.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a receiving apparatus according to an embodiment of the present invention.

FIG. 2 is a flowchart for explaining the operation of the embodiment.

FIG. 3 is a block diagram illustrating a configuration of a transmission device according to another embodiment of the present invention.

FIG. 4 is a diagram showing a sequence of control information in the embodiment.

FIG. 5 is a flowchart for explaining the operation of the embodiment;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 ... Antenna 12 ... Low noise amplifier 13 ... Reception input changeover switch 14 ... 1st mixer 15 ... Frequency synthesizer 16 ... Bandpass filter 17 ... Amplifier 18 ... 2nd mixer 19 ... Local oscillator 20 ... Low-pass filter 21 ... Demodulator 22 ... Data regenerator 23 Level detector 24 CPU 31 Modulator 32 First mixer 33 Local oscillator 34 Bandpass filter 35 Amplifier 36 Second mixer 37 Frequency synthesizer 38 Bandpass filter 39 Power amplifier 40: transmission output changeover switch 41: antenna 42: CPU

Continued on the front page (58) Fields surveyed (Int.Cl. ⁶ , DB name) H04B 1/02-1/04 H04B 1/06 H04B 1/16-1/24 H04B 1/38-1/58

Claims (2)

(57) [Claims] 1. A wireless transmission / reception device comprising a transmission device and a reception device, wherein the reception device selectively amplifies a received signal and a signal amplified by the amplification device and a signal not amplified. Selecting means for extracting the received signal as a receiving input, a level detecting means for detecting the level of the received signal, and, when the received signal level detected by the level detecting means becomes excessive, the selecting means by the amplifying means. Control means for controlling selection of a signal not to be amplified , wherein the control means has upper and lower threshold levels.
In the state where the upper threshold level is set,
The received signal level detected by the detection means is
When the threshold level is exceeded,
To select a signal that is not amplified by the means
And set the threshold level to the lower threshold level.
With the lower threshold level set.
The received signal level detected by the bell detecting means is lower than the lower limit.
When the value falls below the threshold level on the
It will be in a state to select the signal amplified by the amplification means
And the threshold level is set to the upper threshold level
A wireless transmission / reception device characterized in that: 2. A radio transmitting / receiving apparatus comprising a transmitting device and a receiving device, wherein the transmitting device selectively amplifies a transmission signal and a signal amplified by the amplifying device and a signal not amplified. Selecting means for taking out as a transmission output, and selecting a signal which is not amplified by the amplifying means, when notified that the received signal level detected by the level detecting means of the partner receiving apparatus has become excessive. and control means for controlling to said control means have a threshold level of the upper side and lower side
In the state where the upper threshold level is set,
The received signal level detected by the detection means is
When the threshold level is exceeded,
To select a signal that is not amplified by the means
And set the threshold level to the lower threshold level.
With the lower threshold level set.
The received signal level detected by the bell detecting means is lower than the lower limit.
When the value falls below the threshold level on the
It will be in a state to select the signal amplified by the amplification means
And the threshold level is set to the upper threshold level
A wireless transmission / reception device characterized in that: