JP2000115013A - Dual band transmitting/receiving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of parts, current consumption and an unnecessary spurious occurrence source by supplying a first local oscillation frequency to transmission source signals, adapting them as a transmission intermediate frequency signal, supplying the second local oscillation frequency to the transmission intermediate frequency signals and adapting them as a transmission frequency signal. SOLUTION: The TX-IQ input signals of transmission is subjected to quadrature modulation through the use of VHF local signals from a local oscillation part 2 and a synthesizer 2 by a modulating part MOD and is outputted. The quadrature-modulated signals are limited in band by an intermediate frequency stage and an intermediate frequency filter (TX-IF-FIL), converted in frequency by a frequency converting stage (TX-MIX) through the use of UHF local signals from the local oscillation part 1 and the synthesizer 1 and outputted. The frequency-converted signals are amplified by a driver, limited in band by a transmission frequency filter 1 (TX RF FIL 1) or the transmission frequency filter 2 (TX RF FIL 2) and, then, outputted as transmission outputs (TX OUT).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dual-band transmission / reception system that can use a common intermediate frequency band in two bands, such as an 800 MHz band to which transmission and reception communication frequencies of a digital car telephone system are allocated and a 1.9 GHz band. About the machine.

[0002]

2. Description of the Related Art Conventionally, as a dual band wireless communication apparatus, as disclosed in Japanese Patent Application Laid-Open No. H10-145262, a PDC (Personal Digital Cellular)
This is a two-band transmission / reception device that can be shared between digital transmission / reception with an S (Personal Handyphone System) and operates a VCO so that a VCO of a local oscillation circuit can be shared with a PLL to obtain a dual-band VCO. The PDC uses a reception frequency of 810-826 MHz, a VCO that oscillates at 680-696 MHz, and a transmission frequency of 940-956 MHz.
S performs transmission / reception communication using a reception frequency of 1895-1918 MHz and a VCO oscillating at 1651-1674 MHz and a transmission frequency of 1895-1918 MHz.
Indicates that the fundamental local oscillation frequency and its harmonic frequency are used.

[0003] Japanese Patent Application Laid-Open No. 10-84299 discloses a dual time division multiplexing (TDMA) system in which a frequency division multiplexing (FDD) system and a time division (TDD) system can be used in one device. Regarding the band radio, the reception frequency of 810-826 MHz and 68
VCO oscillating at 0-696MHz, 130MHz intermediate frequency and 940-
956MHz transmission frequency, 1895-1918M in TDD mode
VCO oscillating at 1635.15-1657.95MHz with a receiving frequency of Hz
Using an intermediate frequency of 260 MHz and a transmission frequency of 1895-1918 MHz, simultaneous transmission / reception is possible by switching a plurality of switches and switching the transmission / reception in a time period that is extremely short as compared with the audio signal to perform transmission / reception. Also, multiple TD
D In a dual-band radio, when switching between transmission / reception mode and switching between transmission and reception, the subdivided circuit portions are combined using a matrix switch to limit a dedicated circuit only in a specific mode or a specific frequency band. To share circuit components.

Japanese Patent Application Laid-Open No. 10-107676 discloses that, for example, in the FDD / TDMA communication system, two local oscillation frequencies and an oscillation frequency for offset are used, and specifically, a transmission A band of 940-960 MHz is used. 810-830MHz reception band A ', while 915-940MHz transmission band B and 86
In the reception band B 'of 0-885 MHz, the difference between the two transmission bands and the reception band is 130 MHz and 55 MHz, so that the sharing is achieved with the offset frequency of 75 MHz.

Japanese Patent Laid-Open Publication No. Hei 8-223307 discloses two bands, such as an 800 MHz band (810-956 MHz) and a 1.5 GHz band (1429-1501 MHz), to which transmission and reception communication frequencies of the digital car telephone system are assigned. The dual-band transceiver can be used in common, and the two received signals are one local intermediate frequency signal and one common intermediate frequency signal. The first band is a reception frequency of 810-826 MHz, a VCO oscillating at 680-696 MHz, an intermediate frequency of 130 MHz and a transmission frequency of 940-956 MHz, and the second band is 1471.
-1501MHz reception frequency and reception V oscillating at 1347-1371MHz
Transmission / reception communication is performed using a CO, a transmission VCO of 1169-1193 MHz, and a transmission frequency of 1429-1453 MHz, and dual band transmission / reception is enabled at three local oscillation frequencies. Third, with two local oscillation frequencies and an appropriate mixer,
An example in which the local oscillation frequency is generated is also shown.

Next, a conventional dual band transceiver is replaced with a GSM of European mobile phone.
(Global System for Mobile Communication, GS
M) and the European personal mobile communications system DCS1
800 (Digital Cellular System 1800, DC
S) will be described as an example with reference to FIG. First, the transmission system in the 900 MHz band will be described. The quadrature IQ signal for TX is transmitted to the local oscillator 2 and the synthesizer 2 (Synthesizer2 + VCO
Using the VHF local signal from 2), quadrature modulation is applied by MOD via SW1. Here, the quadrature-modulated signal is band-limited through TX-IF-FIL. This signal is transmitted to the local oscillator 1 and the synthesizer 1 (Synthesizer1 + V
TX-MIX using UHF local signal from CO1)
To convert the frequency and amplify it with the driver (DRIVER). After band-limiting the amplified signal by TX-RF-FIL, the signal is output as TX-OUT.

Next, the receiving system will be described. Received signal RX-
IN is amplified by LNA (low noise amplifier) via RX-RF-FIL. This signal is frequency-converted by RX-MIX using UHF local signals from local oscillator 1 and synthesizer 1 (Synthesizer1 + VCO1), and RX-IF-F
After passing through the IL, the signal is amplified by a variable gain amplifier (AGC-amp.). This signal is sent to local oscillator 2 and synthesizer 2 (Synthe
Using the VHF local signal from the (sizer2 + VCO2), the demodulation unit DEM performs quadrature demodulation and outputs an RX-IQ signal.

Next, the transmission / reception system in the 1.9 GHz band has the same basic operation as the 900 MHz band described above, and switches between the local oscillator 1 and the synthesizer 1 (Synthesizer + VCO) used for local signals. Hereinafter, this will be described.

First, a UHF local signal used in the 900 MHz band is transmitted to a local oscillator 1 and a synthesizer 1 (Synthesizer 1 + V).
The local oscillator 3 and the synthesizer 3 (Synthesizer3 + VCO3) are used for the 1.9 GHz band. The VHF local signal used in the 900 MHz band includes a local oscillator 2 and a synthesizer 2 (Synthesizer2 + VCO2).
However, SW1 is switched, and in the 1.9 GHz band, the local oscillator 4
And a synthesizer 4 (Synthesizer4 + VCO4).

[0010]

However, in the dual-band communication system disclosed in each of the above publications, three or more local oscillation frequencies or two local oscillation frequencies and an offset local oscillation frequency, and two local oscillation frequencies and a third local oscillation frequency are used.
When a complicated configuration is required to use a mixer for generating the local oscillation frequency, and a small size and light weight are required, the size and weight must be further simplified and further reduced.

Further, as can be seen from the configuration shown in FIG. 3, a conventional dual band transceiver (Dual band transceiver) is used.
transceiver) has the following problems.

The first problem is that the number of parts is large because four systems of a local oscillator and a synthesizer (Synthesizer + VCO) are required.

The second problem is that the current consumption is large because four systems of the local oscillator and the synthesizer (Synthesizer + VCO) are required.

A third problem is that four signal sources having different frequencies are used.
Therefore, there is a high possibility of generating unnecessary spurious.

An object of the present invention is to provide a dual band transceiver which reduces the number of components, reduces current consumption, and reduces unnecessary spurious sources.

[0016]

SUMMARY OF THE INVENTION The present invention relates to a dual band transmitting / receiving apparatus for transmitting / receiving a transmission / reception frequency signal in a first radio frequency band and a transmission / reception frequency signal in a second radio frequency band at the same intermediate frequency. On the side, a transmission first mixer that supplies a first local oscillation frequency to a transmission original signal to generate a transmission intermediate frequency signal, and a second local oscillation frequency that supplies a second local oscillation frequency to the transmission intermediate frequency signal to generate a transmission frequency signal. A receiving second mixer that supplies the second local oscillation frequency to a reception signal to provide a reception intermediate frequency signal, and a reception second mixer that supplies the reception intermediate frequency signal to the reception intermediate frequency signal. A reception first mixer that supplies a local oscillation frequency to obtain a reception original signal.

Further, in the above-mentioned dual band transmitting / receiving apparatus, a transmission intermediate frequency band filter is provided between the transmission first mixer and the transmission second mixer, and a driver is provided at an output of the transmission second mixer, and a driver of the driver is provided. A first filter for selecting an output and a second filter for transmission are provided, and a linear amplifier is provided in front of the second mixer for reception and the first reception filter for selecting two received signals in front of the linear amplifier. And a reception second filter, and a reception intermediate frequency band filter is provided between the reception second mixer and the reception first mixer.

In the above-mentioned dual band transmitting / receiving apparatus, the transmission original signal is an orthogonal signal transmission original signal, the transmission first mixer modulates the orthogonal signal, and the reception original signal is an orthogonal signal reception signal. An original signal, wherein the reception first mixer demodulates the signal into a quadrature signal.

In the above-mentioned dual band transmitting / receiving apparatus, the first local oscillation frequency and the second local oscillation frequency are each composed of a local oscillation section and a synthesizer for varying the oscillation frequency of the local oscillation section. I do.

Further, in the dual band transmitting / receiving apparatus, a π / 4 phase difference circuit which can be turned on / off is provided on a path for supplying the transmission intermediate frequency signal to the second local oscillation frequency.

In the above-mentioned dual-band transmitting / receiving apparatus, the first radio frequency band and the second radio frequency band are GSM of a European mobile phone and DCS of a European personal mobile communication system. I do.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments according to the present invention will be described.
This will be described in detail with reference to the drawings.

[First Embodiment] (Configuration of the present embodiment) Referring to FIG.
Dual-band transmitting and receiving apparatus (Dual b
and transceiver) are shown. As an example, a dual-band transceiver capable of transmitting and receiving GSM of a European mobile phone and DCS of a European personal mobile communication system will be described.

In the figure, the upper part shows a transmitting system, the middle part shows a synthesizer, and the lower part shows a receiving system.

First, the configuration of the transmission system will be described together with the basic signal flow. Transmit TX-IQ input signal to local oscillator 2 and synthesizer 2 (Synthesizer2 + VCO2)
, Using the VHF local signal from the MOD, and performing quadrature modulation in the modulation unit MOD and outputting the result. After band-limiting the quadrature-modulated signal with an intermediate frequency stage and an intermediate frequency filter (TX-IF-FIL), the local oscillator 1 and the synthesizer 1 (Synt
hesizer1 + VCO1) using UHF local signal
The frequency is converted by a frequency conversion stage (TX-MIX) and output. The frequency-converted signal is amplified by a driver (DRIVER), band-limited by a transmission frequency filter 1 (TX RF FIL1) or a transmission frequency filter 2 (TX RF FIL2), and then output as a transmission output (TX OUT).

Next, the configuration of the receiving system will be described together with the basic signal flow. After the reception (RX IN) input signal is band-limited by the reception frequency filter 1 (RX RF FIL1) or the reception frequency filter 2 (RX RF FIL2), the signal is amplified by the low noise amplification stage (LNA) and output. This amplified signal is transmitted to the local oscillator 1 and the synthesizer 1 (Synthesizer1 + VCO
Using the UHF local signal from 1), the frequency is converted by the reception frequency mixing stage (RX MIX) and output. After band-limiting the frequency-converted signal with an intermediate frequency amplification stage and an intermediate frequency filter (RX IF FIL), the variable gain control stage (A
GC amp.) To amplify and output. This amplified signal is sent to a local oscillator 2 and a synthesizer 2 (Synthesizer2 + VCO2).
, And performs quadrature demodulation by the demodulation unit DEM using the VHF local signal from the controller and outputs the received signal as a quadrature signal (RX IQ).

The local oscillator 1 and the synthesizer 1
Receives a local oscillation circuit by variable voltage control and a local oscillation frequency signal of the local oscillation circuit, divides the frequency by a programmable frequency divider, compares the divided frequency signal with a predetermined reference frequency signal, and determines the difference. By supplying a corresponding control signal to the local oscillation circuit, a stable local oscillation frequency signal can be obtained. With the same configuration for the local oscillator 2 and the synthesizer 2, a highly reliable and stable local oscillation frequency signal can be obtained.

(Explanation of Operation of the Present Embodiment) The operation will be described based on the basic signal flow described in the configuration of the present embodiment.

In this embodiment, in order to realize a dual band transceiver with a minimum local oscillator and a synthesizer (Synthesizer + VCO), these are realized by a dual band of two signal bands. Must be shared. For that purpose, assuming that a general 900 MHz band system and a 1.9 GHz band system have dual bands, the following conditions (frequency) must be satisfied.

FUHF = (900 MHz + 1.9 GHz) /2=1.4 GHz (1) fVHF = 1.9 GHz-1.4 GHz = 1.4 GHz-900 MHz = 500 MHz (2) where fUHF is Local oscillator 1 and synthesizer 1 (Synth
esizer1 + VCO1) is the frequency of the UHF local signal oscillated, and fVHF is the local oscillator 2 and the synthesizer 2 (Synth 2).
esizer2 + VCO2) is the frequency of the VHF local signal that oscillates.

To further mention, the first local oscillation frequency is the center frequency between two bands, and the second local oscillation frequency is the difference between the high frequency (1.9 GHz) and this center frequency, In addition, this center frequency and low frequency (900M
Hz).

A signal that satisfies this condition is a dual band and has the following signal relationship. First, in the transmission system, a signal obtained by orthogonally modulating a transmission orthogonal (TX IQ) signal at 500 MHz is frequency-converted using a 1.4 GHz UHF local signal, and each of the 900 MHz and 1.9 GHz signals is transmitted to a transmission frequency filter 1 (TX RF filter 1). FIL1) and transmission frequency filter 2 (TX RF FIL2) limit the band to the required frequency (900 MHz or 1.9 GHz), and then output it as transmission output (TX OUT).

Next, in the receiving system, 900 MHz, 1.9 G
Hz signal to receive frequency filter 1 (RX RF FIL
1) After inputting after limiting the band to the required frequency (900MHz or 1.9GHz) with the reception frequency filter 2 (RX RF FIL2),
A quadrature demodulation is performed on a 500 MHz signal that has been frequency converted using a 1.4 GHz UHF local signal, and the received quadrature signal (RX I
Output as Q).

Referring to FIG. 1, GSM and DCS will be described below.
In this frequency band, a specific example of the frequency relationship of a dual band transceiver will be described using the present embodiment.

The transmission and reception frequencies of GSM and DCS are as follows.

GSM transmission frequency: fGT = 890 to 915 MHz GSM reception frequency: fGR = 935 to 960 MHz DCS transmission frequency: fDT = 1805 to 1880 MHz DCS reception frequency: fDR = 1710 to 1785 MHz Frequency fGc
Center frequency fDcenter including enter and DCS transmission / reception
Is as follows.

FGcenter = 925 MHz fDcenter = 179 MHz From these two frequencies and equations (1) and (2), the UHF local frequency fUHFcenter and the VHF local frequency fVHFcenter are: In practice, each system has a frequency bandwidth. Therefore, considering the DCS having a wider frequency bandwidth, U
When calculating the HF local frequency fDUHFmin and the VHF local frequency fDUHFmax, It is. Similarly for GSM, It is.

As can be seen from the above calculation results, the UHF local frequency of the DCS having a wider frequency bandwidth is G
Includes that of SM. Here, the dual band transceiver described as an example can be constituted by two local oscillation circuits capable of generating the following frequencies. fUHF = 1275 MHz to 1445 MHz fVHF = 435 MHz Further, the dual band transceiver (Dual band transc
eiver) has an intermediate frequency for reception of fVHF = 435MHz
Becomes The relationship is that the transmission intermediate frequency is fVHF = 435 MHz even in the transmission intermediate frequency amplification stage, and the same intermediate frequency filter by the same intermediate frequency amplification stage is sufficient.

[Second Embodiment] The basic configuration of a second embodiment of the present invention is the same as that of the first embodiment shown in FIG. The means for supplying the local oscillation signal is different. The configuration is shown in FIG. In FIG. 2, a first local oscillation frequency (fUHF) is a center frequency between two bands, and a second local oscillation frequency is a difference between a high frequency (1.9 GHz) and this center frequency, and The difference between the center frequency and the low frequency (900 MHz) is the same as in the first embodiment. In addition, the same reference numerals are given to the same portions in other configurations, and duplicate description will be omitted.

In FIG. 2, a transmission mixer (TX MIX)
Is composed of an image rejection mixer,
Local oscillator 1 and synthesizer 1 (Synthesizer1 + VCO1)
Is input to the transmission mixer (TX MIX) via a 90-degree phase shifter (π / 2 phase difference circuit). By switching the 90-degree phase signal from this 90-degree phase shifter and the local signal that passes through the 90-degree phase shifter with a switch, the transmission output (TX OUT) is imaged through a 900 MHz or 90-degree phase shifter. 1.9GHz of wave
Can output only a single frequency.

As a result, the transmission output (TX OU
Transmission output filter 1 (TX RF FIL1) and transmission output filter 2 (TX RF FIL1) needed to extract T)
2) becomes unnecessary. Therefore, it is possible to further reduce the number of components, and it is also possible to suppress occurrence of unnecessary spurious.

As described above, the embodiment according to the present invention has been described. As described above, an example in which the GSM system and the DCS system can be transmitted and received by one dual-band transmitting and receiving apparatus has been described. PDC
(Personal Digital Cellular) and PHS (Personal Ha
The present invention is also applicable to the case where the relationship between one carrier frequency and the other carrier frequency is a relationship between image frequencies or a relationship of two or more times. Applicable.

[0043]

As described above, the present invention has the following effects.

First, a local oscillator and a synthesizer (Synt
Hesizer + VCO) can be realized by two systems, so that the number of parts can be reduced.

Second, a local oscillator and a synthesizer (Synt
Hesizer + VCO) can be realized by two systems, so that current consumption can be reduced.

Third, since there are only two signal sources having different frequencies, there is an effect that the possibility of generating unnecessary spurious is low.

[Brief description of the drawings]

FIG. 1 is a block diagram of a dual-band wireless transmitting / receiving apparatus according to the present invention.

FIG. 2 is a block diagram of a dual band wireless transmitting / receiving apparatus according to the present invention.

FIG. 3 is a block diagram of a conventional dual-band wireless transceiver.

[Explanation of symbols]

 TX-IQ Transmit quadrature signal MOD modulator TX-IF-FIL Transmitter intermediate frequency band filter TX-MIX Transmitter mixer DRIVER Transmit power amplifier VCO1,2 First and second local oscillator (variable frequency oscillator) RX-RF -FIL1,2 Receiving-side receiving frequency band filter RX-MIX Receiving-side mixer RX-IF-FIL Receiving-side intermediate frequency band filter AGCamp Variable gain amplification control unit DEM demodulation unit

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[Procedure amendment]

[Submission date] August 2, 1999 (1999.8.2)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

Claims (6)

[Claims] 1. A dual band transmitting / receiving apparatus for transmitting / receiving a transmission / reception frequency signal in a first radio frequency band and a transmission / reception frequency signal in a second radio frequency band at the same intermediate frequency. A transmission first mixer that supplies one local oscillation frequency to produce a transmission intermediate frequency signal, and a transmission second mixer that supplies a second local oscillation frequency to the transmission intermediate frequency signal to produce a transmission frequency signal. A receiving second mixer that supplies the received signal with the second local oscillation frequency to obtain a received intermediate frequency signal;
A receiving first mixer for supplying the first local oscillation frequency to the receiving intermediate frequency signal to obtain a receiving original signal; 2. A transmission intermediate frequency band-pass filter is provided between the transmission first mixer and the transmission second mixer, and a driver for an output of the transmission second mixer and a transmission terminal for selecting an output of the driver. A first filter and a second transmission filter, and a first amplifier and a second filter for selecting a linear amplifier in front of the second mixer for reception and the two reception signals in front of the linear amplifier. The dual band transmitting / receiving apparatus according to claim 1, further comprising: a receiving intermediate frequency band filter between the receiving second mixer and the receiving first mixer. 3. The transmission original signal is a transmission original signal of a quadrature signal, the transmission first mixer modulates the quadrature signal,
3. The dual band transmitting / receiving apparatus according to claim 1, wherein the received original signal is an original signal for receiving a quadrature signal, and the first mixer for reception demodulates the quadrature signal. 4. The local oscillation frequency according to claim 1, wherein the first local oscillation frequency and the second local oscillation frequency are each composed of a local oscillation unit and a synthesizer that varies the oscillation frequency of the local oscillation unit. 4. The dual band transmitting / receiving device according to 3. 5. The transmission second mixer includes a π / 2 that can be turned on / off in a path for supplying the second local oscillation frequency.
4. The dual band transmitting / receiving apparatus according to claim 1, further comprising a phase difference circuit. 6. The first radio frequency band and the second radio frequency band are based on GSM (Global System
for Mobile Communication) and DCS1800, a personal mobile communication system in preparation for practical use in Europe
The dual band transmitting / receiving apparatus according to any one of claims 1 to 5, wherein the transmitting / receiving apparatus is a (Digital Cellular System 1800).