JPH07297750A - Transmission/reception mixer circuit - Google Patents

Abstract

PURPOSE:To reduce power consumption of a local oscillator by providing a changeover distributer through which other input of a reception and a transmission mixer is outputted for a reception and a transmission time slot. CONSTITUTION:A reception signal is received from an antenna 1 for a reception time slot and amplified by a low noise amplifier 3 via a transmission/reception changeover device 2, band-limited at a BPF 4, frequency-converted by a reception mixer 5 to obtain a reception IF signal. The transmission signal is frequency-converted by a transmission mixer 6 for a transmission time slot, band-limited by a BPF 6, amplified to specified power by a transmission power amplifier 8 and sent from the antenna 1 via a changeover device 2. A distribution changeover device 10 is controlled by a switching control signal to give an output of a 1st local oscillator 11 to the mixer 5 or 6 for transmission reception time slots while being switched to the transmission reception sides. Then gallium arsenide FET switch is used for the changeover device 10 to reduce the loss, then an output level of the oscillator 11 is reduced and then the power consumption of the oscillator 11 is decreased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency transmission / reception mixer circuit used in a microwave digital mobile radio device.

[0002]

2. Description of the Related Art A personal handy phone (PHP) is being put to practical use as a digitization of a cordless telephone system. This PHP uses the 2 GHz band, and time division multiple access (TDMA).
Time Division Duplex (TDD), which is a transmission method and uses carriers of the same frequency in time division for transmission and reception.
ex) method is adopted. The terminal device of the above digital cordless telephone system is composed of a master unit and a slave unit, and the slave unit is being reduced in size and weight so that it can be easily carried, and low power consumption is being promoted.

FIG. 3 is a diagram showing a circuit configuration example of a high frequency stage and a transmission / reception mixer circuit portion of a conventional terminal mobile unit. In the figure,
1 is an antenna for both transmission and reception, and 2 is a transmission / reception switch, which is a transmission control time slot of each frame assigned to the mobile device by a switching control signal from a control unit (microprocessor) that controls the operation of the entire mobile device. And it is switched according to the reception time slot. 3 is a low noise amplifier for amplifying the received signal, 4 is a band pass filter (BP)
F) and 5 are mixers on the receiving side, which mix the received signal passed through the BPF 4 and the first local oscillation signal a output from the first local oscillator 11 with the local oscillation signal b distributed by the distributor 9. It outputs a received IF signal containing one intermediate frequency (IF) component. Reference numeral 6 denotes a transmission side mixer, which mixes a transmission signal output from a modulator (not shown) and a local oscillation signal c distributed by the distributor 9 and outputs the mixed signal. 7 is a BPF,
A signal in a predetermined band is selectively output from the output signal of the mixer 6. The output of the BPF 7 is amplified by the power amplifier 8, and the switch 2 transmits the transmission wave of the transmission time slot from the antenna 1.

FIG. 4 is a block diagram of the distributor 9 in the conventional circuit of FIG. (A) is an example of a resistor divider,
(B) is a hybrid transformer shown as an example of the reactance distributor.

[0005]

However, in the above conventional configuration, there is a distribution loss of the distributor. Since the resistance divider has a loss of 6 dB and the reactance divider has a loss of 3 dB, it is necessary to set the output level of the first local oscillator 11 in consideration of the loss. Therefore, there is a problem that the power consumption of the first local oscillator 11 increases. Further, since the local oscillator signals b and c are always supplied to both the transmitting and receiving mixers, for example, while receiving in the reception time region,
The first local oscillator signal c input to the transmission side mixer 6 is amplified by the transmission power amplifier by coupling and reaches the antenna end. That is, unless the isolation up to the antenna 1 at the first local oscillator frequency is large, there is a problem that the leakage power of the first local oscillator signal at the antenna end at the time of reception becomes large. Further, when a reactance distributor having a small loss is used, it is difficult to realize it by using a semiconductor, so that there is a drawback that it cannot be arranged in an integrated circuit (IC).

An object of the present invention is to solve the above-mentioned problems in the prior art, reduce power consumption, realize an IC, and prevent leakage of the first station-originated signal at the antenna end. It is to provide a small transmit / receive mixer circuit.

[0007]

A transmitting / receiving mixer circuit of the present invention uses a TDMA transmission system to amplify a received signal of an antenna of a time division duplex system and band-limit a high frequency signal as one input to generate a first local oscillation signal. A receiving mixer for frequency-converting as the other input and outputting a signal including the first intermediate frequency signal;
The operation of the entire radio is the transmission mixer that outputs the frequency-converted signal from the modulator as one input and the first local oscillation signal as the other input, the first local oscillator, and the output of the first local oscillator. In response to a switching control signal from the control unit that controls the output signal, the output signal is output as the other input of the reception mixer when the reception slot is assigned to the radio device, and the transmission mixer is output when the transmission slot is assigned to the radio device. And a switching distributor that outputs as the other input of the above. Further, the switching distributor is configured by using a gallium arsenide FET and a resistor. Is.

[0008]

FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, 1 to 8 and 11 are indicated by using the same reference numerals as in the case of the conventional configuration of FIG. Reference numeral 10 is a distribution switching device showing the main components of the present invention. The reception signal is input from the antenna 1 to the reception time region (reception time slot), passes through the duplexer 2, is amplified by the low noise amplifier 3,
The band is limited by the BPF 4, the frequency is converted by the reception mixer 5, and the reception IF signal is obtained. The transmission signal is input to the transmission mixer 6 in the transmission time domain (transmission time slot), frequency-converted, band-limited by the BPF 7, amplified to a specified power by the transmission power amplifier 8, and passed through the transmission / reception switch 2 to the antenna 1 Sent from.

The distribution switch 10 is controlled by a switching control signal from a control unit (not shown) which controls the operation of the entire radio, and outputs the output of the first local oscillator 11 to a predetermined transmission / reception time region. The transmission side and the reception side are switched and input to the mixer 5 or the mixer 6. The loss of the distribution switch 10 can be realized at 1 dB or less by using, for example, a GaAs (gallium arsenide) FET switch. Therefore, the output level of the first local oscillator 11 can be made lower than in the conventional case, and the power consumption is reduced.

FIG. 2 is a detailed circuit diagram of the distribution switch 10 shown in FIG. This example is a configuration example of a GaAs FET switch, and is an example using four FETs. The local oscillator signal a from the first local oscillator 11 is switched and output to the first local oscillator signal b given to the receiving side mixer 5 or the first local oscillator signal c given to the transmitting side mixer 6 by the switching control signal. For example, in the reception time region, since the input signal a is output as the first local oscillation signal b to the reception side mixer 5, a control signal is applied to the gates of FET ₁ and FET ₂ to make FET ₁ “closed” and FET ₂ "Open" at the same time, at the same time, the control signal with the opposite polarity is given to the gates of FET ₃ and FET ₄ ,
ET ₃ is “open” and FET ₄ is “closed”. That is,
FET ₄ on the side connected to the transmitter mixer 6 is "closed"
Since there is no leakage due to coupling with the mixer 6,
There is only a low level due to the isolation within the distribution switching circuit 10. GaAs FET illustrated in FIG.
In the case of the switch, the isolation in the microwave band was about 20 dB or more. In the transmission time domain, by switching the switching control signal to the opposite polarity, four FETs ₁
~ FET ₄ should just be made into the reverse state, respectively. In any case, the loss when outputting the output signal b from the input signal a and the output signal c from the input signal a is 1 dB or less.

[0011]

As described in detail above, the following effects can be obtained by implementing the present invention. (1) The power consumption of the first local oscillator can be reduced. (2) Since the distribution switch is small, it can be easily integrated into an IC. (3) Since the antenna end leakage power is suppressed, the required characteristics for the BPF are alleviated.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing a partial detailed circuit example of FIG.

FIG. 3 is a conventional circuit block diagram.

FIG. 4 is a circuit example diagram of a conventional distributor.

[Explanation of symbols]

 1 Antenna 2 Switcher 3 Low Noise Amplifier 4,7 BPF 5,6 Mixer 8 Power Amplifier 9 Distributor 10 Distribution Switcher 11 First Local Oscillator

Claims (2)

[Claims] 1. A first intermediate frequency signal obtained by frequency-converting a high-frequency signal, which is obtained by amplifying and band-limiting an antenna reception signal of a time division duplex system by a TDMA transmission system, as one input and a first local oscillation signal as the other input. A receiving mixer that outputs a signal including a signal, a transmitting mixer that outputs a signal from the modulator as one input and a first local oscillation signal that is frequency-converted and output as the other input, a first local oscillator, and the first local oscillator. The output of the oscillator is output as the other input of the receiving mixer in the case of the receiving slot assigned to the radio by the switching control signal from the control unit that controls the operation of the entire radio and is assigned to the radio. A transmission / reception mixer circuit comprising: a switching distributor that outputs the other input of the transmission mixer when the transmission slot is set. 2. The switching divider is a gallium arsenide FET
And a resistor. 3.
The transmit / receive mixer circuit described.