JPH0425227A - Transmitter-receiver - Google Patents

Abstract

PURPOSE:To reduce the number of local oscillators by sending each output of the local oscillator and a phase shifter via a hybrid and an antenna. CONSTITUTION:A reception signal from an antenna 3 at the time of receiving is given from a hybrid section 4 to mixers 5, 6 and a modulated local oscillation signal from a phase shifter 2 and a local oscillator 1 is superimposed on the reception signal to the mixers 5, 6. The output of the mixers 5, 6 is a low frequency demodulated output via an intermediate frequency low frequency processing section 7. Moreover, the modulated local oscillation signal from the phase shifter 2 and the local oscillator 1 is sent from an antenna 3 via the hybrid section 4 at the transmission. Thus, small power duplex transmission reception of small size is obtained by using one local oscillator (one frequency) in common for transmission and reception.

Description

[Detailed Description of the Invention] [Summary] To provide a transmitter/receiver that reduces the number of local oscillators as much as possible, regarding a low power wireless transmitter/receiver or a weak radio wireless transmitter/receiver used for a small power wireless device for premises/teleterminal. For the purpose of
A phase shifter that shifts the phase; a hybrid section that divides the received signal from the antenna into two; and a hybrid section that combines the received signal distributed by the hybrid section, the output of the phase shifter, and the output of the local oscillator, respectively. and an intermediate frequency/low frequency processing section that generates a demodulated output from the outputs of both the mixers. and configured to transmit via the antenna.

[Industrial application field]

The present invention relates to a transmitter/receiver, and more particularly to a low power wireless transmitter/receiver or a weak radio wireless transmitter/receiver used in a small power in-plant wireless device/teleterminal.

In recent years, the number of systems using low-power wireless has increased significantly, and since low-power wireless and weak wireless have low output, there is a desire for miniaturization, and with the reduction in power consumption, the size of batteries has also been reduced. It will be done.

Therefore, in order to realize miniaturization of batteries, there is a need for a transmitter/receiver with a simple device configuration that has both a transmitting function and a receiving function.

[Conventional technology]

FIG. 13 shows the configuration of a conventional transceiver. During transmission, the changeover switch 103 is connected to the side shown by the dotted line, and the first local oscillator 1 (11) modulates the carrier wave and the amplifier The signal is amplified at 102 and transmitted from an antenna 104.

Further, during reception, the selector switch 103 is connected to the side shown by the solid line, and the high-frequency reception signal from the antenna 104 is transferred to the local part from the second local oscillator 105 by the mixer 106 using the double super-heterodyne reception method. The mixed signal is mixed with the oscillation signal and converted into a first intermediate frequency signal corresponding to the input difference component by a bandpass filter 107, and this first intermediate frequency signal is further converted into a local oscillation signal from the second local oscillator 108 by a mixer 109. It is mixed with a second intermediate frequency signal through a band pass filter 110 and converted into a second intermediate frequency signal.
The signal is sent to the low frequency processing section 111.

In the intermediate frequency/low frequency processing section 111, the second intermediate frequency signal is limited to a constant amplitude by a limiter amplifier 111A to remove amplitude modulation components such as noise, and then the second intermediate frequency signal is passed to a frequency discriminator 111B.
The frequency is detected by the amplifier 111C, and a demodulated output is obtained by the amplifier 111C.

Furthermore, in FIG. 14, a filter 120 is used in place of the changeover switch 103 in FIG. 13, and among these, a band reject filter 120a sends the transmitted signal to the antenna 104 and removes the received signal. Yes, the band reject filter 120b transfers the received signal to the mixer 10.
6, and the transmitted signal is removed.

In the case of the conventional example described above, two local oscillators are required only on the receiving side because a double super-heterodyne reception method is adopted, but zero intermediate frequency reception as shown in Figure 15 In the case of this method, only one local oscillator 121 is required, and this local oscillation signal is converted to π/
After phase shifting by 2, the received signal from the antenna 125, the output of the phase shifter 122, and the output of the local oscillator 121 are combined by mixers 123 and 124, respectively, and a demodulated output is generated by the intermediate frequency/low frequency processing section 126. It has gained.

However, in the case of this conventional example, the oscillation frequency F of the local oscillator 121 is the same as the frequency F of the received carrier wave, so the mixers 123 and 124 output the frequency deviation signal ΔF as the input difference component (and the input sum component). ) will be output.

Then, in the intermediate frequency/low frequency processing section 126, the mixer 1
23. Each output of 124 is passed through a low-pass filter 126)A,
126) After extracting only the low frequency component (input difference component) at B and removing the amplitude modulation component at limiter amplifiers 1262A and 1262B, both are combined at the combining section 1263, converted to a low frequency signal, and the demodulated output is taken out. That's what I do.

Note that the frequency deviation signal is obtained in two channels in this way because the frequency of the local oscillator 121 and the reception frequency are the same, so the frequency modulation component of the reception signal is on the + side with respect to the carrier frequency F. This is because it is unclear whether there is one side or one side.

[Problem to be solved by the invention]

In all of these conventional examples, the local oscillator is
Since one or three are required and these are composed of discrete components, this has been an obstacle to miniaturization.

Therefore, an object of the present invention is to provide a transceiver in which the number of local oscillators is reduced as much as possible.

[Means and effects for solving the problem] Fig. 1 shows the basic configuration of the present invention, in which a local oscillator l which is modulated by a modulation input and has the same frequency as the received carrier wave is used.
, a phase shifter 2 that shifts the phase of the output of the local oscillator l by π/2, a hybrid section 4 that divides the received signal from the antenna 3 into two, and a received signal divided by the hybrid section 4 and the two mixers 5 that generate a frequency deviation signal by respectively synthesizing the output of the phase shifter 2 and the output of the local oscillator 1;
．． 6, and an intermediate frequency/low frequency processing section 7 that generates a demodulated output from the outputs of both the mixers 5 and 6. I am trying to send it via 3.

As a result, during reception, the received signal from the antenna 3 is given from the hybrid section 4 to the mixer 5.6, but the received signal from the phase shifter 2 and the local oscillator 1 is sent to the mixer 5.6. Since the modulated local oscillation signal is superimposed, the output of the mixer 5.6 passes through the intermediate frequency/low frequency processing section 7 and becomes a low frequency demodulated output.

Also, during transmission, the modulated local oscillation signal from the phase shifter 2 and the local oscillator l is transmitted from the antenna 3 via the hybrid section 4, and one local oscillator (
Compact, low-power duplex transmission and reception that combines transmission and reception with a single frequency) is realized.

FIG. 2(a) shows another basic configuration of the present invention, in which a local oscillator 1 is modulated by a modulation input and has the same frequency as the received carrier wave, and the output of the local oscillator 1 is 2, a hybrid section 4 that distributes the received signal from the antenna 3, the received signal from the hybrid section 4, the output of the first phase shifter 2, and the local oscillator. two mixers 5 and 6 which generate a frequency deviation signal by combining the outputs of both mixers 5 and 6, and an intermediate frequency/low frequency processing section 7 which generates a demodulated output from the outputs of both mixers 5 and 6; a high-pass filter 8 that passes only the high-frequency output component of the mixer 5; a second phase shifter 9 that shifts and sums the output of the other mixer 6 by π/2; The device further includes a high-pass filter 10 that passes only the high-frequency output component of No. 9, and the outputs of both high-pass filters 8 and 10 are combined by the hybrid section 4 and transmitted from the antenna 3. It is.

In this case, only the modulated input components of the local oscillator 1, which are components of the input sum outputted from the mixers 5 and 6, are extracted by the high-pass filters 8 and 10 and are transmitted from the hybrid section 4 via the antenna 3. This allows it to be sent. The purpose of the phase shifter 9 is to match the phase of the local oscillator 2 with that of the phase shifter 2, combine the signals, and send the synthesized signals to the hybrid section 4.

In the case of the figure (b), the hybrid part 4 of the figure (a)
Instead, a switch that can be switched depending on the time of transmission or reception can be used.

Moreover, in the case of FIG. 2(C), a circulator may be used instead of the hybrid section 4 of FIG. 4(a).

Furthermore, as shown in FIG. 4(d), the second phase shifter 9 includes a phase-advancing device 91 and a phase-delaying device 92, and a changeover switch 93 for switching between the two in accordance with transmission or reception. It is also possible to use

The action at this time is shown in FIG. 3, and by switching the selector switch 93, the phase of the output of the mixer 5 and the phase of the output of the mixer 6 can be made to be in phase or in opposite phase. In this case, the signals are combined and transmitted from the hybrid section 4 via the antenna 3, and in the case of opposite phases, they are canceled and are not transmitted, so they are used as a reception mode.

FIG. 4 shows the principle of yet another configuration of the present invention. In addition to the configuration of the present invention shown in FIG. The circuit 21 further includes a spreading code generating circuit 22 which generates a spreading code by the output of the synchronizing circuit 21 and spreads the spectrum of the modulation input to the local oscillator 1.

Thereby, the modulation input to the local oscillator l can be spread spectrum and transmitted.

FIG. 5 shows the principle of yet another configuration of the present invention, in which the antenna 3 is connected to both mixers 5.6 as a reception-only antenna without using the hybrid section 4 as described above,
A transmitting antenna 12 is connected to the output of both high-pass filters 8 and 10.
It is possible to perform duplex communication without considering switching between transmission and reception.

FIG. 6 shows the principle of yet another configuration of the present invention, in which a local oscillator l is modulated by a modulation input and has the same frequency as the received carrier wave, and the output of the local oscillator 1 is A phase shifter 2 that shifts the phase by 2, a first switch 4 that receives a signal from the antenna 3 during reception, and the first switch 4
the received signal, the output of the phase shifter 2, and the local oscillator 1
two mixers 5.6 that generate a frequency deviation signal by combining the outputs of both mixers 5.6, intermediate frequency/low frequency processing section 7 that generates a demodulated output from the outputs of both mixers 5.6, and the local oscillator. a second switch 11 that sends the output of 1 to the phase shifter 2 or a mixer 6 not connected to this phase shifter 2 during reception and to the first switch 4 during transmission; The first switch 4 transmits the output of the local oscillator 1 from the antenna 3 during transmission.

With such a configuration, the transmission system can transmit the modulated signal from the local oscillator 1 from the antenna 3 by switching the first and second switch 4.11.

FIG. 7 shows the principle and part of still another configuration of the present invention, in which, in addition to the above-mentioned configurations, the gain of the modulation input is controlled by the demodulation output of the intermediate frequency/low frequency processing section 7. and a sidetone adjustment section 24 that uses the output of the gain control section 23 to offset sidetone components due to the modulation input in the demodulated output.

This is because when modulation is applied to the local oscillator 1, the modulation component applied to the local oscillator 1 appears in its own demodulated output.
This modulation component in the demodulated output is canceled out to suppress the output.

In this way, the present invention actively guides the local oscillation output, whose radiation was suppressed in the past, to the antenna and uses it as a transmission wave.
This greatly simplifies the configuration of the device, and also enables duplex communication using a single frequency, which was previously impossible.

〔Example〕

FIG. 8 is a circuit diagram showing an embodiment of the hybrid section shown in FIG. 1, and the input terminal A of the antenna 3 and the input terminal B of the mixer 5 shown in FIG. 1 are connected by a coil L1. and the input terminal A of the antenna 3 and the input terminal C of the mixer 6
are connected by coil L2. And coil L
1 and L2 are connected at one end and connected via a resistor R at the other end. In addition, input terminal A,
B.

Capacitors CI, C2, and C3 are connected to ground, respectively.

In the operation of the hybrid section with such a configuration, first, the received signal from terminal A is in phase and sent to terminals B and C by 1/2.
output one by one. Also, 1 with modulation from terminal B
The L/2 shifted local oscillation signal is output to terminal A with 3 dB attenuation, but does not appear at terminal C.
The local oscillation signal modulated by is output to terminal A with 3 dB attenuation, but does not appear at terminal B.

In this way, terminals B and C are separated so that local oscillation signals whose phases are shifted by π/2 do not interfere with each other.

FIG. 9 shows an embodiment of the intermediate frequency/low frequency processing section 7 used in the present invention, and this processing section 7 basically consists of the intermediate frequency/low frequency processing section 126 shown in FIG. and a low-pass filter 71A for each output system of the mixer 5.6.

71B, amplifiers 72A, 72B, limiter 73A,
73B, sine wave converters 74A, 74B, and mixers (balanced modulators) 75A, 75B are connected in series in this order, and the outputs of the mixers 75A, 75B are combined by a synthesizer 78, and further frequency discrimination An analog demodulated output is obtained from the converter 79. Further, the mixer 75A is directly given the local oscillation signal from the local oscillator 76, and the mixer 75B is given the local oscillation signal from the local oscillator 76 by π.
/2 phase shifter 77.

In operation, each mixer 5.6 outputs the sum component and difference component of the local oscillation signal of the local oscillator l and the received signal, and first, the low-pass filters 71A and 71B output the lower difference component. Only ΔF can pass, and after being amplified by amplifiers 72A and 72B, the amplitude modulation components are removed by limiters 73A and 73B, and the amplitude is further limited by limiters 73A and 73B. The resulting rectangular wave is converted to a sine wave converter 74A, 74B converts it into a sine wave and supplies it to mixers 75A and 75B.

The mixers 75A and 75B mix the sine wave with a frequency shift of +ΔF (or one ΔF of 90° phase difference) with the local oscillation signal of an arbitrary frequency F° from the local oscillator 76, thereby generating +ΔF (or Output F'±Δ with a frequency shift of -F) of 90° phase difference and only the phase differs.
Generate F.

Therefore, the synthesized output of the synthesizer 78 becomes F'±ΔF, and if this is discriminated by the frequency discriminator 79, an FM demodulated analog output can be obtained.

In other words, DSB (double-side band) is a signal with a 90° phase difference.
By creating and combining them, one sideband wave cancels out and becomes zero, and the other sideband wave joins together and becomes SS
The demodulated signal is obtained using the same method used to generate B (single sideband).

FIG. 10 shows an embodiment of the intermediate frequency/low frequency processing section when the received signal to the antenna 3 is an FSK wave.
In this embodiment, the rectangular wave output of the limiter 73A is used as the D input, and the output of the limiter 73B is used as the clock signal.
A digital demodulated output can be obtained by passing through the flip-flop 80.

FIG. 11 shows the configuration shown in FIG. 7 in an easy-to-understand manner. When the audio from the microphone 31 is amplified by the amplifier 32 and sent to the local oscillator 1 via the modulator 33, the output of the amplifier 32 is When the delayed signal is delayed by a fixed delay amount determined in advance by the delay amount adjuster 34 and sent to the differential amplifier 34, the received demodulated signal contained in the analog output of the intermediate frequency/low frequency processing section 7 is processed by the differential amplifier 35. Of the demodulated signals of the local station and the demodulated signal of the local station, only the received demodulated signal is extracted, and a desired analog signal is obtained through the amplifier 36 and the speaker 37.

FIG. 12 shows a case in which the configuration of FIG. 11 is further taken into account the gain by the gain control section 23 shown in FIG. 7, and the delay 1i1! of FIG. 11 is taken into account. an amplifier 38 for amplifying the local modulation signal delayed by the adjuster 34; and the amplifier 38
A resistor R3 that provides the output of
, a resistor R2 that connects this - input terminal to the ground potential, and a resistor R1 that connects the - input terminal to the output terminal of the differential amplifier 35. The self-station demodulated signal is applied to the input terminal of the differential amplifier 35.

In such a configuration, when viewed from the input terminal of the differential amplifier 35, the resistor R3 is substantially equivalent to being grounded since the output impedance of the amplifier 38 can be regarded as zero, and therefore, the resistor R3 is equivalent to being grounded. Since R3 can be treated as a parallel connection circuit, the received demodulated signal and the local demodulated signal are R1=
When R2=R3, the following equation is obtained, and the output is obtained with a gain of three times.

Furthermore, since the output impedance of the differential amplifier 35 can be regarded as zero when viewed from the amplifier 38, the resistor R1
is grounded, and the resistors R1 and R2 are in parallel, so the output of the amplifier 38 is attenuated to R3 + R1 · R2 / (R1 + R2) 3 and is applied to the single power terminal of the amplifier 35. Become.

Therefore, if the amplifier gain is set so that the local station modulation signal, which is three times as large as the local station demodulated signal, can be obtained from the output of the amplifier 38 in the same phase, the ten power and the single power of the differential amplifier 35 will have the same phase and amplitude. It will not appear in the output of the differential amplifier 35.

In this way, sidetone adjustment can be performed on the local station demodulated signal.

〔Effect of the invention〕

As explained above, according to the transceiver according to the present invention,
Since duplex communication is achieved by using one local oscillator for both transmission and reception, it is possible to simplify the device and achieve downsizing and lower power consumption.

Furthermore, since duplex communication is possible with one frequency, it greatly contributes to the effective use of frequencies.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the basic configuration of a transceiver according to the present invention. FIG. 2 is a block diagram of another basic configuration of a transceiver according to the present invention. FIG. 3 is a part of the operation of the present invention. FIG. 4 is a block diagram of still another fundamental configuration of the transceiver according to the present invention; FIG. 5 is a block diagram of still another fundamental configuration of the transmitter/receiver according to the present invention; FIG. 6 is a block diagram showing still another basic configuration of a transceiver according to the present invention; FIG. 7 is a block diagram partially showing still another basic configuration of a transceiver according to the present invention; FIG. is a circuit diagram showing an embodiment of the hybrid section used in the present invention; FIGS. 9 and 10 are block diagrams each showing an embodiment of the intermediate frequency/low frequency processing section used in the present invention; FIG. and FIG. 12 are block diagrams specifically showing the configuration of FIG. 7, FIGS. 13 and 14 are block diagrams showing the configuration of a conventional transceiver, and FIG. 15 is a block diagram showing the configuration of a conventional transmitter/receiver. FIG. 2 is a block diagram showing the configuration of a zero intermediate frequency receiver. In the figure, 1... Local oscillator, 2, 9... Phase shifter, 3... Antenna, 4... Hybrid part (switching part), 5.6... Mixer, 7... Intermediate frequency/low frequency processing section, 8.10...High-pass filter. In the figures, the same reference numerals indicate the same or corresponding parts.

Claims (9)

[Claims] (1) A local oscillator (1) which is modulated by a modulation input and has the same frequency as the received carrier wave;
A phase shifter (2) that shifts the phase of the output of 1) by π/2; A hybrid section (4) that divides the received signal from the antenna (3) into two; two mixers that generate a frequency deviation signal by respectively synthesizing the received signal with the output of the phase shifter (2) and the output of the local oscillator (1);
5) (6); and an intermediate frequency/low frequency processing section (7) that generates a demodulated output from the outputs of both the mixers (5) and (6), the local oscillator (1) and the phase shifter ( A transceiver characterized in that each output of 2) is transmitted via the hybrid section (4) and the antenna (3). (2) A local oscillator (1) that is modulated by the modulation input and has the same frequency as the received carrier wave;
A first phase shifter (2) that shifts the phase of the output of 1) by π/2, a hybrid section (4) that distributes the received signal from the antenna (3), and a received signal from the hybrid section (4). and the output of the first phase shifter (2) and the output of the local oscillator (1), respectively, to generate a frequency deviation signal.
5) (6), an intermediate frequency/low frequency processing section (7) that generates demodulated output from the outputs of both mixers (5) and (6), and only the high frequency output component of one mixer (5) passing through. a high-frequency filter (8) that shifts the output of the other mixer (6) by π/2; The antenna (3) further includes a high-pass filter (10) that passes only the output component; A transmitter/receiver that is characterized by its ability to transmit more. (3) The transceiver according to claim 2, characterized in that, in place of the hybrid section (4), a switch that can be switched depending on the time of transmission or reception is used. (4) The transceiver according to claim 2, characterized in that a circulator is used in place of the hybrid section (4). (5) As the second phase shifter (9), one for phase advancement (91
), a slow phase one (92), and a changeover switch (93) for switching between the two depending on the time of transmission or reception. (6) A synchronization circuit (21) that detects synchronization from the output of the intermediate frequency/low frequency processing section (7), and generates a spreading code from the output of the synchronization circuit (21) and sends it to the local oscillator (1). Spreading code generation circuit (2) that spectrally spreads the modulation input of
3. The transceiver according to claim 2, further comprising: 2). (7) The antenna (
3) is connected to both mixers (5) and (6) as a reception-only antenna, and a transmission antenna (12) is connected to the output of both high-pass filters (8) and (10). The transceiver according to claim 2. (8) A local oscillator (1) which is modulated by the modulation input and has the same frequency as the received carrier wave;
a phase shifter (2) that shifts the phase of the output of 1) by π/2; a first switch (4) that receives a signal from the antenna (3) during reception; and the first switch (4). The received signal from the phase shifter (2)
and the output of the local oscillator (1), respectively, to generate a frequency deviation signal.
), an intermediate frequency/low frequency processing section (7) that generates a demodulated output from the outputs of both mixers (5) and (6), and an intermediate frequency/low frequency processing section (7) that generates a demodulated output from the outputs of both mixers (5) and (6);
) or a second switch (11) that sends the signal to the mixer (6) not connected to the phase shifter (2), and sends the signal to the first switch (4) during transmission; A transceiver characterized in that a switch (4) transmits the output of the local oscillator (1) from the antenna (3) during transmission. (9) Adjust the gain of the modulation input to the intermediate frequency/low frequency processing section (
a gain control unit (23) controlled by the demodulated output of 7);
9. Any one of claims 1 to 8, further comprising a sidetone adjustment section (24) for canceling a sidetone component due to the modulation input in the demodulated output using the output of the gain control section (23). Transmitter/receiver described in Crab.