JP3056172B2 - Mobile phone equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable telephone device having different types of receiving / transmitting mechanisms and capable of communicating with each communication system, and more particularly to a portable telephone device having a common reference frequency.

[0002]

2. Description of the Related Art Two systems, such as PHS and PDC, are
In a dual-type telephone device having two housings, it is common practice to share each element, but the reference frequency used in the frequency synthesizer and the modulation / demodulation circuit of each system is Different in the system.

FIG. 2 shows an example of a conventional dual type telephone device. As shown in FIG. 2, the telephone device 50
This is a dual-type telephone device having two systems, such as S and PDC, each having a transmission unit 4, 14, a reception unit 6, 16 and the like. Oscillator 32, 34 for oscillating a reference frequency is provided for each communication system, and supplies a predetermined frequency. Therefore, the number of components is increased, and the mounting area is increased.

On the other hand, when trying to share these,
The frequency synthesizer can be shared, but since the reference frequencies used in the modulation circuit and the demodulation circuit are different, it is necessary to create a frequency that can be shared inside the modulation and demodulation circuit.

As a method for solving this problem, Japanese Patent Laid-Open Publication No.
Japanese Patent Application Laid-Open No. 130291 discloses an invention that prepares a frequency having the least common multiple of frequencies used in each system, uses this frequency as a common frequency, and divides this frequency to obtain a required frequency. ing.

[0006]

However, in general, modulation and demodulation circuits are individually developed for each system and integrated, and when a common modulation and demodulation circuit is used for each system, a dedicated integrated circuit is developed. There is a need to do. In particular, when a conventional LSI is used, Japanese Unexamined Patent Application Publication No.
When the frequency of the least common multiple of both systems is divided and used as in the method described in JP-A-91,
The internal circuit of the LSI has to be changed in accordance with it, such as changing the frequency division ratio of the LSI, and there has been a problem that much cost and labor are required for development cost, development lead time, and the like.

[0007]

According to the present invention, in order to solve the above-mentioned problems, a portable telephone device is constituted as follows.

That is, in a portable telephone device having two communication systems, such as functions of a digital car telephone device (hereinafter, referred to as PDC) and a second generation cordless telephone device (hereinafter, referred to as PHS) in the same housing,
The frequency which is the greatest common divisor of the different reference frequencies in each individual device of the PHS and the PHS is set as a common reference frequency, and the common reference frequency is multiplied to a frequency required in each system for use.

More specifically, the highest common divisor of the two frequencies, 4.8 MHz, is used as a reference, and its frequency is multiplied by 3 to 14.4 MHz.
Is used as the reference frequency of the PDC, and this frequency is supplied to the frequency synthesizer and the modulation / demodulation circuit.
3.2 MHz is set as the second local oscillator of the receiving circuit. Also PHS
For the side, 4.8 MHz is quadrupled to 19.2 MH
z is supplied to the frequency synthesizer and the modulation / demodulation circuit.

Thus, the reference oscillator for generating the reference frequency of the portable telephone device can be operated by one common oscillator, instead of being individually arranged for each system. A conventional LSI can be used without omitting and changing internal circuits, etc.
The circuit can be configured at low cost.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a portable telephone device according to the present invention will be described with reference to FIG.

FIG. 1 shows a telephone device 2 having a PHS and PDC communication system.

As shown in FIG. 1, the telephone device 2 has a PDC and a PHS communication circuit in one housing, and can communicate with any communication system. That is, the telephone device 2 includes a PDC unit 30 and a PHS unit 40, and the PDC unit 30 includes a transmitting unit 4, a receiving unit 6, a frequency synthesizer 8, a 3 × 3 circuit, and a 9 × 5 circuit.
And a modulation / demodulation unit 10, while the PHS unit 40 similarly has a transmission unit 14, a reception unit 16, and a frequency synthesizer 1.
8, a quadruple frequency multiplier 7, and a modulation / demodulation unit 20.

The transmitters 4 and 14 and the receivers 6 and 16 are ordinary transmitters and receivers, and the signals received by the receivers 6 and 16 are demodulated by the modem 10 or 20.
Also, the signals modulated by the modulation / demodulation unit 10 or 20 are transmitted from the transmission units 4, 14, and the like.

Further, the frequency used in PHS is 19.2.
MHz, and the frequency used in the PDC is 14.
Since the frequency is 4 MHz, a common oscillator 9 for transmitting a frequency of 4.8 MHz, which is the greatest common divisor of the two, is arranged substantially at the center of both. The common oscillator 9 is connected to the tripler circuit 3 and the fourth multiplier circuit 7 and sends out a common frequency of 4.8 MHz.

The tripler circuit 3 comprises a frequency synthesizer 8,
It is connected to a 9-multiplier circuit 5 and a modulation / demodulation unit 10, and sends out a reference frequency of 14.4 MHz to each of them.

That is, the tripler circuit 3 uses the output of the common frequency of 4.8 MHz as the reference frequency of the PDC by multiplying the output of the common frequency of 3 by 14.4 MHz, and supplies the frequency to the 9-multiplier circuit 5, the frequency synthesizer 8 and the modulation / demodulation circuit 10. And 9 more
An output of a frequency of 129.6 MHz is sent from the multiplying circuit 5 to the receiving unit 6 to be the second local oscillator.

On the PHS side, a quadruple frequency multiplier 7
Is connected to the frequency synthesizer 18 and the modem unit 20,
A reference frequency of 19.2 MHz is transmitted to each of them. That is, the quadruple circuit 7 supplies 19.2 MHz obtained by quadrupling the 4.8 MHz reference frequency to the frequency synthesizer 18 and the modulation / demodulation circuit 20.

(Description of Operation) Next, the operation of the telephone device 2 will be described.

First, when the telephone device 2 is operated as a PDC, the common frequency from the common oscillator 9 is 4.8 MHz.
z is input to the tripler circuit 3 of the PDC unit 30, and an output having a frequency of 14.4 MHz from the tripler circuit 3 is supplied to the frequency synthesizer 8, the 9-multiplier circuit 5, and the modulation / demodulation circuit 10, respectively. Further, the frequency from the 9-multiplier circuit 5 is 129.6 MH.
The output of z is used as the second local oscillator and is mixed with the first intermediate frequency. Thereby, it is operated as a PDC.

When the telephone device 2 is operated as the PHS, the frequency is input to the quadruple circuit 7 of the PHS unit 40 using 4.8 MHz from the common oscillator 9 as a reference. Here, the frequency is set to 19.2 MHz, and the output is supplied to the frequency synthesizer 18 and the modulation / demodulation circuit 20 to operate the telephone device 2 as a PHS.

Thus, the necessary frequency can be supplied to the communication circuits of both the PDC and the PHS, and the communication can be performed in any system. As described above, according to the telephone device 2, it is possible to communicate with both the PDC and the PHS systems, and furthermore, the common oscillator 9 can be used as a common oscillator for oscillating the reference frequency, and the number of parts can be reduced. Cost can be reduced.

In the above example, the telephone apparatus 2 provided with a PDC and a PHS has been described as an example. However, the present invention is not limited to this, and another system or two or more systems may be used. Further, the common frequency is not limited to the greatest common divisor frequency of both systems, and may be a lower frequency.

[0024]

According to the portable telephone device of the present invention, the PDC
Each of the PHSs and PHSs does not require an expensive temperature-compensated oscillator, but requires a large number of development costs and lead time by realizing the required frequency of each system with the configuration of one common oscillator and a multiplication circuit. There is no need to develop a dedicated integrated circuit for the modulation / demodulation circuit, and the cost can be reduced because an expensive temperature-compensated oscillator can be eliminated, and the mounting area can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing one embodiment of a mobile phone device according to the present invention.

FIG. 2 is a diagram showing a conventional example.

[Explanation of symbols]

 2 Telephone device 3 Tripler circuit 4, 14 Transmitter 5 9 Multiplier circuit 6, 16 Receiver 7 Quadrupler circuit 8, 18 Frequency synthesizer 9 Common oscillator 10, 20 Modulator / demodulator 30 PDC section 40 PHS section

Claims (2)

(57) [Claims] A plurality of communication circuits each having a reception unit, a transmission unit, a modulation / demodulation unit, a frequency synthesizer, and a multiplication circuit having a predetermined multiplication factor, wherein a maximum of each reference frequency used in the communication circuit is A common oscillating means for oscillating a common divisor frequency is provided in common to the communication circuit, and the frequency of the common oscillating means is multiplied to a predetermined reference frequency in the multiplying circuit and used as a reference frequency for each communication circuit. Mobile phone device. 2. A communication circuit comprising a plurality of receiving circuits, a transmitting circuit, a modulating / demodulating circuit, a frequency synthesizer, and a multiplying circuit having a predetermined multiplying factor. A common divisor frequency is oscillated by common oscillating means, a frequency oscillated by the common oscillating circuit is commonly supplied to the communication circuit, and the frequency is multiplied to a predetermined reference frequency in the multiplying circuit. A frequency oscillation system for a mobile phone device, wherein the frequency oscillation system is used for a reference frequency.