JPS59117831A - Burst tone type radio communication system - Google Patents

Abstract

PURPOSE:To eliminate an unpleasant tone when a voice is intermitted and to solve a problem on application at the rapid change in the signal strength by transmitting a burst tone to an intermediate part between formants with intermission to eliminate the burst tone at a receiver side. CONSTITUTION:A notch filter 19 and a mixer 20 are inserted between a microphone 1 and a modulator 2 of a transmission circuit, and a burst tone generator 21 is connected to the mixer 20. A notch filter 27 is inserted between an amplifier 14 and a speaker 15 of a receiving circuit. A tone signal is transmitted to an intermediate part between the formants at the transmission side with intermission, and the burst tone is eliminated by the notch filter at the receiving side. As a result, the unpleasant tone generated when the voice is intermitted is eliminated and the problem on applications when the signal strength is changed rapidly is solved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a Perstton type SSB wireless communication system.

The conventional SSN wireless communication system includes a transmitter circuit shown in FIG. 1 and a receiver circuit shown in FIG. 2.

In the transmitter circuit shown in FIG. 1, the microphone 1, the modulator 2, the filter 3, the mixer 4, the power amplifier 5, and the antenna 6 are connected in cascade. A local oscillation frequency is supplied to each from a local oscillator 8.

In the receiver circuit of FIG. 2, the antenna 9, mixer 10 and S
SB filter i1, intermediate frequency amplifier 12 and demodulator 13
, an amplifier 14 and a speaker 15 are connected in cascade, and an AGC circuit 16 is provided between the connection point between the intermediate frequency amplifier 12 and the demodulator 13 and the intermediate frequency amplifier 12,
A local oscillator 17 is connected to the mixer 10, a carrier oscillator 18 is connected to the luma demodulator 13, and a local oscillation frequency output and a carrier frequency output are respectively supplied.

Such conventional SSB wireless communication systems have problems in use, such as unpleasant noises occurring when audio is interrupted, and signal strength changing rapidly as in mobile communications in urban areas.

The present invention has been made in order to eliminate this drawback in view of the above, and embodiments will be described below in detail with reference to the drawings. A transmitter circuit and a receiver circuit showing one embodiment of the present invention, in which the same parts as in FIGS. 1 and 2 are given the same reference numerals.

That is, in the transmitter circuit, a notch filter 19 and a mixer 20 are inserted in cascade between the microphone 1 and the modulator 2, and a burst ton generator 21 is connected to the mixer 20. The A-Stton generator 21 is, for example, a circuit as shown in FIG. and the analog switch 24 are connected in cascade, and from the connection point between the low frequency oscillator 22 and the low pass filter 23, the square wave generator 25 and the low/bus filter 26 are connected.
It is connected to the analog switch 24 to control it.

FIG. 7 shows waveforms at each connection point of the burst ton generator 21, in which the low-frequency waveform from the low-frequency oscillator 22 is shown in figure A, and the waveform after passing through the low-pass filter 23 is shown in figure B. Furthermore, the waveforms that have passed through the square wave generator 25 and the low-pass filter 26 are shown in Figure 0 and Figure D, respectively.

Figure E shows the low frequency waveform B at the analog switch 24.
is controlled using a square waveform to obtain a -Stton waveform.

The output of the i-fusor 20 passes through a modulator 2, an SOB filter 3, a mixer 4, and a power amplifier 5, and is connected to an antenna 6.

Note that the carrier oscillator 7 is connected to the modulator 2, and the local oscillator 8 is connected to the mixer 4, as in the conventional case.

On the other hand, in the receiver circuit, the antenna 9 and the f-fusa 10
and 88B filter/11, intermediate frequency amplifier 12, demodulator 13, amplifier 14 and speaker 15 are connected in cascade,
It is possible to connect the AGC circuit 16 between the connection point between the intermediate frequency amplifier 12 and the demodulator 13 and the intermediate frequency amplifier 12, connect the local oscillator 17 to the mixer 10, and connect the carrier oscillator 18 to the demodulator 13. Although similar to the conventional method, in the present invention, a notch filter 27 is interposed between the amplifier 14 and the speaker 15.

FIG. 5 is a waveform diagram for explaining the transmission waveform on the transmitter side and the action of the notch filter 270 on the receiver side of the present invention. C is transmitted intermittently, and on the receiver side, the characteristic curve d (broken line) of the notch filter 27 removes the burst tone C, and only the voice is reproduced from the speaker.

As explained above, in the wireless communication system of the present invention, the transmitter side and receiver side circuits of the conventional 8SB wireless communication device are not changed in any way, and the transmitter side only has a microphone and a modulator. All you need to do is to install a notch filter and a circuit that mixes the /4-Stoton oscillator between them, and on the receiver side, you can just install a notch filter between the amplifier and the speaker, and it will be fine if the audio is interrupted. It is possible to provide a Perstton wireless communication system that eliminates unpleasant noises that occur during the process and solves problems in use when the signal strength changes rapidly.

[Brief explanation of the drawing]

1 and 2 are block diagrams of a transmitter circuit and a receiver circuit in a conventional SSB wireless communication system, and FIGS. 3 and 4 are block diagrams of a transmitter circuit and a receiver circuit in a Perstton wireless communication system according to an embodiment of the present invention. Block diagram of the circuit and receiver circuit,
FIG. 5 is a waveform diagram for explaining the pulse tone wireless communication system of the present invention, and FIG. 6 shows an embodiment of a pulse tone generator interposed on the transmitter side in the wireless communication system of the present invention. The block diagram, FIG. 7, is a waveform diagram for explaining the operation of the burst ton generator of FIG. 6. 1...Microphone, 2...Modulator, 3,11...
・SSB filter, 4, 10, 20... mixer, 5
...Power amplifier, 6,9...Antenna, 7,18.
...Carrier oscillator, 8. ]7...Local oscillator, 12
...Intermediate frequency amplifier, 13...Demodulator, 14...
Amplifier, 15... Speaker, 16... AGC circuit,
19... Notch filter, 21... Burst ton generator, 22... Low frequency oscillator, 23.26... Low pass filter, 25... Square wave oscillator, 24... Analog switch. Patent applicant Yaesu Musen Co., Ltd.'j,Z Figure ■ 61 Section 1 Fan

Claims (1)

[Claims] A transmitter circuit in which a microphone, a modulator, a filter, a mixer, a power amplifier, and an antenna are connected in cascade, and a receiver circuit in which an antenna, a mixer, a filter, an intermediate frequency amplifier, a demodulator, an amplifier, and a speaker are connected in cascade. In a wireless communication device circuit, a notch filter and a mixer are interposed between a microphone and a modulator in a transmitter circuit, a notch filter and a mixer are connected between the amplifier and a speaker in a receiver circuit, and a notch filter and a mixer are interposed between a microphone and a modulator in a transmitter circuit. The transmitter side transmits a tone signal intermittently between the 17th and 27th ormants, and the receiver side uses a notch filter to remove the burst tone signal. Perstton type wireless communication system characterized by.