JP2583708Y2 - High frequency mobile radio transceiver - Google Patents

Description

[Detailed description of the invention]

[0001]

The present invention is applicable to different frequencies, for example, 8
In each frequency band of 00 MHz or 1,500 MHz, a plurality of sets of wireless transceivers of a mobile communication system such as a heterodyne digital car phone employing various high-frequency modulation schemes are interlocked and switched for each frequency band. The present invention relates to a high-frequency wireless transmission / reception device configured to be able to share a second intermediate frequency stage including a modulator and a receiving stage with a second intermediate frequency stage and subsequent stages.

[0002]

2. Description of the Related Art Conventionally, a heterodyne radio transmitting / receiving apparatus for a modulated carrier frequency in a car telephone uses, for example, a first transceiver A shown in FIG. 2 for an 800 MHz band and a second transceiver B for a 1,500 MHz band. Generally used.

[0003] In FIG. 2, a first transmitter / receiver A includes a frequency conversion unit in which a modulated carrier received by an antenna 1 via a duplexer 8 is offset by an RF amplifier 2, a bandpass filter 3, and a first local oscillator 9. A receiving stage Rx composed of a mixer 4, a band-pass filter 5, an amplifier 6, and a mixer 7 of a frequency conversion unit offset by the second local oscillator 10, and a baseband signal processing unit based on the first local oscillator frequency of the receiving stage. And a transmission stage Tx composed of a modulator 13 that modulates a signal from the demodulation unit 16, a band-pass filter 12, and a power amplifier 11 that amplifies transmission power to the antenna via the duplexer. For example, it is dedicated to transmission and reception in the 800 MHz band.

[0004] The second transceiver B also has the same transmission and reception stages as those of the first transceiver.
Dedicated for sending and receiving bands. And, in order to correspond to the different frequency bands, a movable contact is provided so that each receiving stage and each transmitting stage of each of the first and second transceivers can be switched to each use frequency band A or B, A switch 14-1 in which a fixed contact is connected from the reception stage to a demodulation unit 16, which is a baseband signal processing unit, through a final intermediate frequency stage 15 including a detector, is included in each transmission stage. A switch 14-2 in which a fixed contact is connected to a path from the demodulation unit to the modulator.

[0005]

By the way, in the above-mentioned conventional configuration, the output side of the first intermediate frequency conversion mixer of each receiving stage of the first and second transceivers A and B respectively corresponding to different frequency bands. In addition, since the apparatus includes the band-pass filter 5, the amplifier 6, and the second intermediate frequency stage of the mixer 7, and further includes individual modulators in the transmission stages of the respective transceivers, the external dimensions and weight of the entire device are reduced. In addition to being bulky, there is a problem in that when used in a portable state, the power consumption of the battery is remarkably reduced, and the call communication time is significantly reduced.

[0006]

SUMMARY OF THE INVENTION The present invention eliminates the above-mentioned obstacles, and the second stage of each receiving stage corresponding to each different frequency band.
The first and second subsequent stages including the intermediate frequency stage and the modulator of the transmission stage are unified and shared by the first local oscillator so that the modulator of the transmission stage can be shared with the reception stages of the first and second transceivers. A switch for switching the output of each of the provided frequency conversion mixers to a path leading to a demodulation unit via a system after the first intermediate frequency, and a modulator for modulating a baseband signal from the demodulation unit. A switch for switching to each transmission stage of the second transceiver, and a path from a first local oscillator of the first transceiver and a second local oscillator of the second transceiver for modulation of the modulator. Are provided so as to interlock with a switch for switching between the two.

[0007]

FIG. 1 shows an embodiment of the present invention. In FIG. 1, the same parts as those in FIG. 2 are denoted by the same reference numerals, and the frequency bands A and B having different ranges surrounded by a chain line.
The circuit configuration of the first and second transceivers A and B respectively corresponding to each other is shown. In the second transceiver B, a portion surrounded by a two-dot chain line is the same as the reception stage Rx of the first transceiver A. It has a configuration. The movable contacts A and B of the switches 14-1, 14-2 and 14-3 mean that they are connected to the first and second transceivers A and B, respectively, and the switches are interlocked. . The bandpass filter 5 and the amplifier 6 are referred to as a first intermediate-frequency stage, and the mixer 7 and the intermediate-frequency stage 15 are regarded as a second intermediate-frequency stage including a detector and the like.

When the configuration of the present invention is applied to a digital mobile telephone mobile station, if the transmission frequency of the first transceiver A is 800 MHz, 940 to 956 MHz;
1.429-1.441 GHz when 1.5 GHz
And 1.453 to 1.465 GHz, and the reception frequency is 810 to 826 MHz and 1.5 G in the 800 MHz band.
In Hz, 1.477-1.489 GHz and 1.501
Since the frequency is 1.513 GHz, as shown in FIG.
If the direct modulation method is adopted in the H band, the first local oscillation frequency becomes 9
The first intermediate frequency is 130 MHz from 40 to 956 MHz in relation to the reception frequency. Next, in the 1.5 GHz band, in order to share the system after the first intermediate frequency, the first intermediate frequency must be set to 130 MHz as described above. From the above, taking the lower one as the first local oscillation frequency, 1.347-
From 1.359 GHz and 1.371 to 1.383 GHz, the frequency of the second local oscillator 30 independently provided in the transmission stage of the second transceiver B is determined from the relationship between the first local oscillator frequency and the transmission frequency. It should be 82 MHz.

[0009] Therefore, the first stage is frequency-synthesized so that the first intermediate frequencies of the receiving stages for different use frequency bands are equal, and is modulated to share the modulator 40 for orthogonally modulating the baseband signal from the demodulation unit. The frequency of the local oscillator and the frequency of the second local oscillator are switched by the switch 14-3 for each used frequency band.

[0010]

According to the present invention, the second intermediate frequency is set for different frequency bands by setting the frequency so that the frequency after the first intermediate frequency is equal to the transmission / reception frequency of a wide band. The circuit systems subsequent to the first intermediate frequency including the subsequent stages can be shared, and the first intermediate frequency can be shared.
In addition, since the modulator can be shared by interlocking and switching the second local oscillation frequency by a switch for each different frequency band, a high-frequency modulation heterodyne which is small in size and weight of the whole device, reduced in power consumption and excellent in spurious characteristics. Mobile radio transmitting and receiving apparatus.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram of a high-frequency mobile wireless transmission / reception device of the present invention.

FIG. 2 is a circuit configuration diagram of a conventionally known high-frequency mobile radio transmission / reception device.

[Explanation of symbols]

1,21 antenna 2 RF amplifier 3,5,12,22,24 band pass filter 4,7,23 mixer 6 amplifier 8,28 duplexer 9,29 first local oscillator 10,30 second local oscillator 11 power amplifier 14- 1, 14-2, 14-3 switch 15 intermediate frequency stage 16 demodulation unit 40 modulator A first transceiver B second transceiver Rx reception stage Tx transmission stage

Claims (1)

(57) [Scope of request for utility model registration] 1. A heterodyne type mobile radio transmission / reception apparatus wherein at least two sets of mobile radio transmission / reception apparatuses provided corresponding to different modulation high frequency bands are switched for each use frequency band. A switch that is offset and switches to a path from each of the outputs of the frequency conversion mixers provided in the reception stages of the first and second transceivers to the demodulation unit via the system after the first intermediate frequency and the system after the first intermediate frequency;
A switch for switching to each transmission stage of the first and second transceivers via a modulator for modulating a baseband signal from the demodulation unit; and a switch for modulating the baseband signal with respect to the modulator. A switch for mutually switching a path from a first local oscillator of the first transceiver to a second local oscillator of the second transceiver, and a first intermediate frequency post-stage including a second intermediate frequency stage of a receiving stage A high-frequency mobile radio transmission / reception device characterized in that a modulator for the transmission stage is shared with the transmission stage.