JPS6025327A - Transmitter-receiver for two-frequency duplex operation - Google Patents

Abstract

PURPOSE:To eliminate the need for a frequency converter and an oscillator more expensive than an own station modulation signal eliminating section by eliminating modulation signal returned to the own station with a wave of phase opposite and amplitude equal to an own station modulation signal formed in the own station modulation signal eliminating section. CONSTITUTION:A reception wave is fed to a mixer MIX and mixed with a carrier modulated by the own station modulation signal, and a wave mixed with the own station modulation signal and an opposite station modulation signal is extracted. This wave is fed to an own station modulation signal eliminating section MC. On the other hand, a wave having the same amplitude, opposite phase and same delay time as that of the own station modulation signal is obtained from a part of the own station modulation signal at a delay circuit and a phase inverting circuit in the own station modulation signal eliminating section MC. Since both the waves are added in the eliminating section MC, the modulation signal of the own station is eliminated and only the modulation signal from the opposite station is extracted from a terminal 10 to an external circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION (!1) Technical Field of the Invention The present invention relates to a two-frequency duplex transmitting/receiving device, and more particularly to a transmitting/receiving device for a car telephone.

(bl) Prior Art and Problems FIG. 1 is a block 1'I block connection diagram of a transmitting/receiving device used in a conventional two-frequency duplex system.

In the figure, a carrier wave obtained from an oscillator (not shown) included in the modulator 10D is modulated by a modulation signal applied from a terminal l. The modulated carrier wave is a mixer old X and a local oscillator shared by the transmitter and receiver! , 0 and converted to a predetermined frequency, the signal is amplified to the required power by the power amplifier PA, passes through the duplexer DUP and the terminal 3, and is radiated to the outside from the antenna 8.

On the other hand, the received wave from antenna A passes through terminal 3 and duplexer DUP, and then passes through mixer old X to the local oscillator LO.
After being mixed with the output wave from and converted to an intermediate frequency,
It is demodulated by the demodulator DEM, and the modulated signal from the other station is taken out at terminal 2.

In a transmitting/receiving device having such a configuration, one local oscillator serves as a normally used transmitting local oscillator and a receiving local oscillator, so the number of parts is reduced and the transmitting/receiving device is a simple type.

Note that if a synthesizer is used for the local oscillation LO instead of a crystal oscillator, output waves of a large number of local oscillation frequencies can be obtained.

FIG. 2 is a block connection diagram of a simple transmitting/receiving device conventionally used in the Breathtalk system. Since it is a breath talk system, unlike in FIG. 1, the local station and the other station share the same frequency, and when the local station is transmitting, the other station is in a receiving state and cannot transmit.

In the same figure, by turning on the brain switch (not shown) connected to terminal 5, the Sui-Sochi circuit 5W is turned on.
Since the switch circuit 5W-1 is turned ON and the switch circuit 5W-3 is turned OFF, the modulation signal applied to the terminal 4 is transferred to the modulator MO as described above.
D modulates the carrier wave, and the modulated carrier wave is transmitted to the power amplifier P.
A. Switch circuit! It passes through J-2 and terminal 6 and is radiated to the outside from antenna 8.

On the other hand, when the pre-stoke switch is turned OFF, the switch circuits 5W-1 and 5W-2 return to their original states and enter the receiving state, and the received wave from the antenna 8 applied to the terminal 6 is transferred to the switch circuit 5W-1 and 5W-2. Mixer M through SW~2
Added to IX. Here, it is mixed with a part of the output of an oscillator (not shown) included in the modulator MOD, and the received wave is frequency-converted to an intermediate frequency, demodulated by the demodulator DIEM, and the original modulated signal is taken out from terminal 7. It will be done.

The circuit configuration of FIG. 2 is more simplified than the circuit configuration of FIG. 1.

As mentioned above, when the other station is transmitting, the own station is in the receiving state and the transmitter does not operate, and the output wave for local oscillation supplied from the modulator MOD is an unmodulated wave. This is because it can be used as is.

However, the relationship is such that the difference between the transmitting frequency and the receiving frequency is equal to the intermediate frequency of the receiver.

In the case of simultaneous transmission and reception, using the circuit configuration shown in Figure 2,
When the transmitting and receiving sides talk simultaneously, the modulated local oscillation output wave is added to the mixer MIX, so the demodulator DEM
There is a problem in that the demodulated waves extracted in this process include those from the own station and the other station, making it impossible to extract the modulated waves sent from the other station.

(C1 Object of the Invention The present invention has been made in view of the problems of the prior art described above, and an object of the present invention is to provide a two-frequency duplexing transmitting/receiving device having a simple circuit configuration, low cost, and small size.

(d+ Structure of the Invention The object of the above invention is to provide a means for adding a part of a carrier wave modulated with a modulation signal to a mixer in a receiving section, and a means for delaying and inverting the phase of a part of the modulated signal to a demodulator in the receiving section. This is achieved by providing a two-frequency duplexing transmitting/receiving device characterized in that it includes means for adding to the output signal.

te+ Example of invention FIG. 3 is a block connection diagram of an embodiment of the present invention.

In the figure, MOD stands for the modulator, PA stands for the power amplifier, and DUP
denotes a transmitter/receiver duplexer, AMP an amplifier, MIX a mixer, DEM a demodulator, I device, MC a local modulation signal canceling section, and 8 to 10 terminals, respectively.

Each of these blocks is connected as follows.

In the figure, the input terminal (1) of the modulator MOD is terminal 8 and the own station modulation signal is erased! '111FIC input terminal (7)
The output terminal is the input terminal (2) of the mixer old X and the input terminal to the power amplifier 1], and the output to the power amplifier P is via the input terminal T-(/1.1) of the duplexer then v1
It is connected to the 11th child 9.

On the other hand, the output terminal (5) of the duplexer is connected to the amplifier AMP,
It is connected to the output terminal 10 via the mixer MTX, the JIJ detector DEM, and the local modulation signal canceling unit MC.

The operation of the transmitter/receiver device connected in this way is as follows.

Most of the modulation signal applied from the input terminal 8 is sent to the modulator M.
OD and modulates the carrier wave as described above, part of this output is sent to the mixer old X, and the rest is added to the power amplifier PA where it is amplified to a predetermined level and then passed through the duplexer DUP and terminal 9. It is radiated to the outside from antenna 8.

On the other hand, the received wave from the antenna applied from the terminal 9 is applied to the mixer X through the duplexer DUP and the amplifier IP. Here, it is mixed with a carrier wave modulated by the local station modulation signal, converted to an intermediate frequency, demodulated by a demodulator OEM, and a mixed wave of the local station modulation signal and the partner station modulation signal is extracted. This wave is then applied to the local station modulation signal canceling section MC.

On the other hand, a part of the own station modulation signal is transmitted through a delay circuit and a phase inversion circuit (not shown) in this own station modulation signal erasing section MC.
As a result, a wave 17 having the same amplitude, opposite phase, and the same delay time as the demodulated local station modulation signal is obtained.

Then, the wave with the same amplitude and opposite phase and the same delay time and the demodulated wave obtained by 1q from demodulated:'+'a 11 U M are sent to the adder circuit (not shown) in the local modulation signal canceling section MC. Therefore, the modulated signal of the own station is erased, and only the variable δIMI signal from the other station is taken out from the terminal 10.

In addition, crystal oscillation 3 is used as an oscillator included in the modulator MOD:
) If a single frequency generator is used instead of a single frequency generator, it is possible to transmit and receive using any frequency among a large number of peripheral frequencies that can be generated.

+f) As described in the detailed explanation of the invention, the modulated signal folded back within the own station has an opposite phase to the own modulated signal generated within the own station modulated signal erasing section,
Since it was canceled by waves of the same amplitude, only the modulated signal of the other station could be taken out at the output terminal.

This eliminates the need for a transmitting frequency converter and a local oscillator, which are more expensive than the local modulated signal canceling section, so it is possible to provide a low-cost and compact transmitting/receiving device.

[Brief explanation of the drawing]

Figure 1 shows the connection diagram of the conventional two-frequency duplex power type circuit.
Figure 2 shows the block connection diagram of the conventional prestoring method.
FIG. 3 shows a block diagram of a two-frequency duplex power type according to the present invention. In the figure, MOD is the modulator, PA is the power amplifier 119, and D
IIP indicates a duplexer, AMP an amplifier, old X a mixer, DEM a demodulator, and MC a self-modulated signal canceller.

Claims (1)

[Claims] means for adding a portion of the Ill transmission modified by the modulated signal to a receiver mixer; and means for delaying and phase inverting the portion of the modulating signal and adding it to the output signal of the receiver demodulator. A two-frequency duplex transmitting/receiving device characterized by: