JPS6161735B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to radio equipment, and includes digital signals,
This allows FM signals to be shared in both directions.

Conventionally, in this type of radio device, when applying FM modulation as shown in FIG. ) 5 to obtain the FM modulated wave, phase comparator 8, low frequency converter 9, voltage controlled oscillator (VCO) (e.g. 60MHz) 10, amplifier 1
2, mixer 13, reference oscillator (e.g.
59.545MHz) from a phase lock loop (PLL) circuit consisting of 14 in a mixer 11, and transmits a transmission output wave (for example, 150MHz) to a terminal 15.
It is taken out from. On the other hand, when demodulating FM waves, the received intermediate frequency input (for example, 455 KHz) obtained from the terminal 16 is sent to the wave generator 17 and the intermediate frequency amplifier 1.
8, is demodulated by the FM detector 19, and is output to the amplifier 2.
0, is amplified by the power amplifier 21 and becomes the output of the speaker 22. In the case of a digital signal, the output from the microphone 1 is passed through a digital modulator/demodulator 7 to a phase comparator 8, a low frequency converter 9, a VCO 10, a mixer 13,
The signal is applied to the mixer 11 via a PLL circuit consisting of an amplifier 12 and a reference oscillator 14.

Further, the received input via the wave generator 17 and the intermediate frequency amplifier 18 is applied to the speaker 22 via the PLL circuit, the digital modulator/demodulator 7, and the power amplifier 21. Because of this configuration, compared to radios that only use digital signals, in the case of FM radios, when modulating, the amplitude limiter 2,
Low frequency wave generator 3, modulator 4, oscillator 5, wave generator 6,
When demodulating the mixer 11, there is a drawback that an FM detector 19 and an amplifier 20 must be newly added. 23 is a first switch for switching audio input between FM modulation and digital modulation;
4 is a second switch that switches the demodulation output between FM demodulation and digital demodulation and outputs it to the power amplifier; 25
is a third switch for switching the input to the phase comparator 8 between transmission and reception.

The present invention eliminates such drawbacks and aims to share the digital signal modulation/demodulation circuit and the FM modulation/demodulation circuit,
The aim is to simplify the configuration by reducing the number of newly added circuits for FM modulation and demodulation.

FIG. 1 shows an embodiment of the present invention,
This shows the case where FM modulation is applied directly to the reference oscillator of a PLL circuit with a VCO equal to the transmission frequency, and the VCO control voltage of the PLL circuit is used for demodulation.
The details will be explained below. Here 1-4, 7-1
0, 12 to 18, and 20 to 22 are the same as those with the same symbols in FIG. 2, but the reference oscillator 14 is adapted to be subjected to FM modulation.

The audio signal from the microphone 1 passes through an amplitude limiter 2 and a low frequency generator 3, and is then sent to a modulator 4 to generate a reference oscillator (e.g.
149.545MHz) Apply FM modulation to 14. This 8
Since the PLL circuit formed by 10, 12, and 13 responds to a modulated wave, the output of the VCO 10 directly becomes a modulated wave at a transmission frequency (for example, 150 MHz), and a transmission output wave is obtained from the terminal 15.

On the other hand, the received intermediate frequency input (for example, 455 KHz) obtained from the terminal 16 passes through a wave generator 17, an intermediate frequency amplifier 18, a phase comparator 8, a low frequency wave generator 9,
VCO (e.g. 150MHz) 10, mixer 13, reference oscillator (e.g. 149.545MHz) 14, amplifier 12
Enter the PLL circuit. VCO10 at this time
The control voltage becomes the FM demodulation signal, so this signal is amplified by the amplifier 20 and the power amplifier 21 and sent to the speaker 2.
Audio output can be extracted from 2.

In the case of digital data, the sending and receiving processes are almost the same as those shown in FIG. 2, so the explanation thereof will be omitted.

As explained in the above embodiments, since the reference oscillator making up the PLL circuit is directly FM modulated and the VCO control voltage is used as the FM demodulation signal, compared to the conventional method, the VCO frequency is directly modulated during modulation. Since the transmit frequency can be set, the oscillator,
Wavers, mixers, etc. can be omitted. Also, at the time of demodulation
There is no need to provide an independent FM detector for FM demodulation. Furthermore, during digital modulation, the oscillator,
It has the advantage that wavers and mixers can be omitted. Therefore, if a digital radio device is also equipped with FM modulation/demodulation functions, it has the advantage of being able to significantly reduce circuitry.
Its industrial value is great.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a radio device according to an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional radio device. 1...Microphone, 2...Amplitude limiter, 3...Low frequency generator, 4...Modulator, 5...Oscillator, 6...
wave generator, 7... digital modulator/demodulator, 8... phase comparator, 9... low frequency generator, 10... VCO (voltage controlled oscillator), 11... mixer, 12... amplifier,
13... Mixer, 14... Reference oscillator, 17...
Wave device, 18...Intermediate frequency amplifier, 19...FM
Detector, 20...amplifier, 21...power amplifier,
22...Speaker.

Claims (1)

[Claims] 1. A PLL circuit comprising at least a mixer, a phase comparator, and a VCO, and the output of the mixer is used as one input of the phase comparator, and the output of the phase comparator is used as the control input of the VCO to control the oscillation frequency. , first and second switchers for switching the audio input and output between FM modulation and digital modulation, a digital modulator/demodulator, and the other input of the phase comparator when transmitting from the output of the digital modulator/demodulator. and a third switch for obtaining the intermediate frequency component of the received input at the time of reception, and the mixer for obtaining one input from the output of the VCO and the other input from the reference frequency oscillator. on the occasion
During FM modulation, the audio input is applied to the reference frequency oscillator through the first switch for FM modulation, and during digital modulation, the audio input is applied to the digital modulator and demodulator through the first switch to perform digital modulation. The transmission output is obtained from the VCO through modulation, and when receiving FM demodulation, the received audio output is obtained from the control input of the VCO via a second switch, and when digital demodulation, the VCO is controlled. A radio device characterized in that a received audio output is obtained from an input via a digital modem.