JP3464147B2 - Transceiver - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmitter / receiver used for transmission / reception in the UHF band, microwave band and millimeter wave band used for fixed land communication, satellite communication, mobile communication, etc. The present invention relates to a transceiver having a receiver.

[0002]

2. Description of the Related Art FIG. 7 is a block diagram showing an example of the configuration of a conventional transceiver, in which 1 is an intermediate frequency band signal to be transmitted (hereinafter,
Radio frequency band signal for transmission (hereinafter referred to as IF signal) (hereinafter,
A transmission frequency conversion unit for converting into an RF signal), 2 is a reception frequency conversion unit for converting an input reception RF signal into a reception IF signal, and 3 is a loopback test for performing a loopback test of the RF signal in the own station to confirm system performance. It is a vessel. Also, 1S
Is a transmission IF signal (frequency fTI), 4 is a transmission local oscillator (frequency fTL), 5 is a mixer, 6 is a bandpass filter (hereinafter referred to as BPF), 7 is a transmission RF amplifier, 8 is a switch, and 1W is transmission RF. It is a signal (frequency fTL + fTI). 2W is the received RF signal (frequency fRL + fRI),
9 is a switch, 10 is a receiving RF amplifier, 11 is a BPF, 1
2 is a receiving local oscillator (frequency fRL), 13 is a mixer, 14 is a low pass filter (hereinafter referred to as LPF),
2S is a received IF signal (frequency fRI). Also, 1
5 is a local oscillator, 3S is a local oscillation wave, 16 is a mixer, 1
7 is a BPF.

Next, the operation will be described. Transmission IF signal 1S (frequency fTI) input to the transmission frequency converter 1
Is mixed with the output (frequency fTL) of the transmitting local oscillator 4 in the mixer 5, and | mfTL ± nfTI | (m,
The signal of the frequency component of (n is an integer) is output. Of this signal, the desired frequency component (fTL +
After the signal of (fTI) is selected, it is amplified to a predetermined level by the transmission RF amplifier 7 and output as a transmission RF signal 1W. On the other hand, the reception RF signal 2W (frequency fRL + fRI) input to the reception frequency converter 2 is the reception RF signal.
The BPF is amplified to a predetermined level by the amplifier 10.
After the unnecessary wave is removed by 11, it is mixed with the output (frequency fRL) of the receiving local oscillator 12 in the mixer 13 and output as a signal of a frequency component of | m (fRL + fRI) ± nfRL | (m and n are integers). To be done. A signal having a desired frequency component fRI is selected from this signal by the LPF 14 and output as the reception IF signal 2S.

In such a transceiver, especially a transceiver used as a base station, a loopback tester 3 is often installed in preparation for performing an in-station RF loopback test for confirming system performance. In the example of FIG. 7, the output signal 1W of the transmission frequency converter 1 is input to the loopback tester 3 via the switch 8 during the loopback test. In the folding tester 3, this input signal (frequency fTL + fTI) and the local oscillation wave 3S (frequency fX) which is the output signal of the test signal oscillator 15 are mixed by the mixer 16, and | m (fTL + fT
I) Generate a signal having a frequency component of ± nfX | (m and n are integers). Of this signal, the desired frequency component is BP
It is selected by F17 and input to the reception frequency conversion unit 2 via the switch 9. At this time, the above fX is selected by the following equation. fX = (fTL + fTI)-(fRL + fRI)

[0005]

Since the conventional transceiver is constructed as described above, when the folding tester 3 needs to be provided, a dedicated local oscillator for generating the local oscillation wave 3S is provided. Since the (test signal oscillator 15) must be prepared, the device becomes large and power consumption increases. Further, when the local oscillator of the transmission frequency conversion unit 1 or the reception frequency conversion unit 2 is composed of a frequency synthesizer and the frequency can be switched to a plurality of frequencies, it is necessary to perform a loopback test with an arbitrary combination of frequencies. Therefore, there is a problem that the local oscillation frequency of the folding back tester 3 also has to be changed, which further increases the size of the device and further increases the power consumption.

The present invention has been made in order to solve the above problems, and downsizing a transmitter / receiver having an in-station RF loopback tester for system performance confirmation, reducing power consumption, and simplifying the configuration. It is intended to be

[0007]

[0008]

A transceiver according to claim 1 of the present invention has a single local oscillator in the radio frequency band, and the output of this local oscillator is used as a transmitter frequency converter or a receiver frequency converter. Used for either local oscillation wave,
The output obtained by mixing the output of the local oscillator and the output of the local oscillator for the loopback test is used for the local oscillation wave of the other frequency conversion unit.

According to a second aspect of the present invention , the transceiver does not use a switching device, but controls the operation or non-operation of the folding tester by turning on or off the local oscillation wave.

Further, the transceiver of claim 3, Oite to claim 1, in which the local oscillator is constituted by a frequency synthesizer.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In the following description, portions common to the conventional example will be described using the same reference numerals.

Embodiment 1. FIG. 1 is a block diagram showing a configuration of a transceiver according to the first embodiment. Reference numeral 1 denotes an intermediate frequency band signal to be transmitted (hereinafter referred to as IF signal), a signal in a radio frequency band for transmission (hereinafter referred to as RF signal). Transmission frequency conversion unit for converting the received RF signal into a reception IF signal, and a reception frequency conversion unit for converting the reception RF signal into a reception IF signal. It is a vessel. In the transceiver according to the first embodiment, the frequency of the transmission IF signal and the frequency of the reception IF signal are the same. The transmission frequency conversion unit 1 mixes the transmission local oscillator 4 that outputs a local oscillation wave 1C having an oscillation frequency fTL, the local oscillation wave 1C, and the transmission IF signal 1S (frequency fI) input to the transmission frequency conversion unit 1. And a band pass filter (hereinafter referred to as BPF) 6 that limits the band of the mixed transmission RF signal 1W.
A transmission RF amplifier 7 for amplifying the transmission RF signal 1W (frequency fTL + fI), and the amplified transmission RF signal 1
Switching device 8 for switching the destination of W to the loopback tester 3
It has and. In addition, the reception frequency conversion unit 2 inputs the received RF signal 2W (frequency fRL +
fRI) and a switch 9 for switching between the input signal from the loopback tester 3, a reception RF amplifier 10 for amplifying the reception RF signal 2W, and the amplified reception R
A BPF 11 that removes unnecessary waves of the F signal 2W and a receiving local oscillator 1 that outputs a local oscillation wave 2C having an oscillation frequency fRL.
2, a mixer 13 that mixes the local oscillation wave 2C and the amplified received RF signal 2W, and a low-pass filter (hereinafter referred to as LPF) that extracts the received IF signal 2S (frequency fI) from the mixed signal. ) 14 and. The folding tester 3 mixes the local oscillation wave 1C (frequency fTL) from the transmission local oscillator 4 with the local oscillation wave 2C (frequency fRL) from the reception local oscillator 14.
0, and a BPF 21 that limits the band of the mixed signal and outputs the local oscillation wave 3S used for the aliasing test,
The mixer 16 that mixes the local oscillation wave 3S and the transmission RF signal 1W from the switch 8 of the transmission frequency converter 1 and the BPF 17 that limits the band of the mixed signal are provided. Further, FIG. 2 is a diagram showing a frequency relationship of each signal of the transceiver in the first embodiment, where the horizontal axis represents frequency and the vertical axis represents power. Here, as in the S band satellite communication earth station, the frequency of the RF signal 1W for transmission is the RF for reception.
An example is shown in which the frequency is higher than the frequency of the signal 2W.

Next, the operation will be described. In FIG. 1, the transmission IF signal 1S (frequency fI) input to the transmission frequency conversion unit 1 is mixed with the output signal (frequency fTL) of the transmission local oscillator 4 in the mixer 5, and | mfTL ± nfI
A signal having a frequency component of | (m and n are integers) is output from the mixer 5. Of this signal, the desired frequency component (fT
L + fI) is selected by the BPF 6 and amplified to a predetermined level by the transmission RF amplifier 7, and then the transmission RF
It is output as a signal 1W. On the other hand, the reception frequency converter 2
Received RF signal 2W (frequency fRL + fI)
Is amplified to a predetermined level by the reception RF amplifier 10, and the unwanted wave is further removed by the BPF 11.
In the mixer 13, it is mixed with the output (frequency fRL) of the receiving local oscillator 12, and | m (fRL + fI) ± nf
The signal of the frequency component of RL | (m and n are integers) is the mixer 1
It is output from 3. Of this signal, the signal of frequency fI which is a desired low frequency component is selected by the LPF 14 and output as the reception IF signal 2S.

In a transceiver in which both the transmission and reception IF frequencies are fI, the frequency is (fTL + f) from the transmission frequency converter 1 during the loopback test.
The signal I) is input to the loopback tester 3 via the switching device 8, and is further frequency-converted to the frequency (fRL + fI) of the received RF signal in the loopback tester 3, and the frequency converter 2
The signal is input to the signal processing circuit after the reception RF amplifier 10 of the reception frequency conversion unit 2 via the switch 9 of FIG. At this time, in the folding back tester 3, fX = (fTL + fI) − (fRL + fI) = fTL−
A local oscillator that generates a local oscillation wave having a frequency of fRL is required. However, in the transceiver of the first embodiment, part of the output of the local oscillator for transmission 4 (frequency fTL) and reception / reception are used. After mixing a part of the output of the local oscillator 12 (frequency fRL) in the mixer 20, the BPF 21
By selecting a signal whose frequency is (fTL-fRL) by band limitation by, a local oscillation wave having the frequency fX can be obtained. Therefore, a dedicated local oscillator (test signal oscillator 15) is provided as the loopback tester 3.
It becomes unnecessary to have, and compared with the conventional example (Fig. 7),
The number of local oscillators (test signal oscillators 15) can be reduced, and the device can be downsized, the power consumption can be reduced, and the configuration can be simplified.

Embodiment 2. FIG. 3 is a block diagram showing a configuration of a transceiver according to the second embodiment of the present invention. In FIG. 3, 15 is a local oscillator (frequency f
x), 23 is a mixer, and 24 is a bandpass filter.
The same components as those in FIG. 1 are designated by the same reference numerals. 4 is a diagram showing the frequency relationship of each signal in the transceiver according to the second embodiment of the present invention, where the horizontal axis represents frequency and the vertical axis represents power.

Next, the operation will be described. Here, since the configuration of the reception frequency conversion unit 2 is the same as that of the above-described first embodiment, the operation is omitted. On the other hand, the transmission frequency converter 1
As the local oscillation wave 1C, the signal (frequency fRL + fX) in which the output of the local oscillator 22 (frequency fRL) and the output of the test signal oscillator 15 (frequency fX) are mixed by the mixer 23 and frequency selected by the BPF 24 (frequency fRL + fX) is used. To do. At this time, if the frequencies of the transmitted and received IF signals are both fI, the frequency of the transmission RF signal 1W can be expressed as (fRL + fX + fI) and the frequency of the reception RF signal 2W can be expressed as (fRL + fI). Oscillator 15
The frequency of the output 3S from is (fRL + fX + fI)-(fRL + fI) = fX, and the conventional test signal oscillator 15 can be used as it is. That is, according to the second embodiment, it is possible to reduce the number of transmission local oscillators of the transmission frequency conversion unit 1, reduce the size of the device, reduce power consumption, and simplify the configuration. If the output of the local oscillator 22 is the local oscillation wave 1C of the transmission frequency conversion unit 1 and the mixed and band-limited signal is the local oscillation wave 2C of the reception frequency conversion unit 2, conversely, The local oscillator for reception of the reception frequency converter 2 can be reduced.

Usually, in fixed land communications, satellite communications, mobile communications, etc., the RF frequencies for transmission and reception are often selected relatively close to each other. Taking the S-band satellite communications earth station as an example,
The 2.6 GHz band is used for the transmission RF frequency and the 2.5 GHz band is used for the reception RF frequency. The transmitting local oscillator or the receiving local oscillator reduced in the second embodiment is an S-band local oscillator having such a large size and a complicated configuration. Therefore, by reducing any one of the above local oscillators, the transmitter local oscillator is reduced. The configuration of can be further simplified.

Embodiment 3. FIG. 5 is a block diagram showing a configuration of a transceiver according to the third embodiment of the present invention. The output of the test signal oscillator 15 (hereinafter referred to as local oscillator) is compared with the transceiver of the second embodiment (FIG. 2). An amplifier 25 for amplifying the input) is provided, the amplifier 25 is further connected to a power switch 27 via a power line 26, and the couplers 2 are used instead of the switches 8 and 9 on the transmission side and the reception side, respectively.
8 and 29 are provided, and the turning on / off of the folding back tester 3 is controlled by turning on / off the power switch 27. That is, in the third embodiment, the amplifier 2
When the power source of No. 5 is turned on, the mixer 16 is locally input with the frequency fX, and the loopback tester 3 performs the test operation. Further, since there is no local input to the mixer 16 when the power of the amplifier 25 is off, the folding tester 3 is inactive. In the non-operating state, the interference of the transmitted and received signals is suppressed by the illation of the mixer 16, so that the transmission frequency conversion unit 1 and the reception frequency conversion unit 2 are expensive and have a large size. Since it is possible to switch between operation and non-operation of the folding back tester 3 without using (8, 9), the device can be made compact and inexpensive.

Embodiment 4. 6 is a block diagram showing a configuration of a transceiver according to a fourth embodiment of the present invention, which is different from the second embodiment (FIG. 2) in that the test signal oscillator 15 is used.
Instead of (frequency fX), the frequency of the output signal is fX1,
A frequency synthesizer 3 that can be switched to fX2, ..., FXn
By setting 0, the transmission frequency can be switched between n ways. That is, the transmission RF frequency is (fRL + fX + f
Therefore, if the frequency of the output signal of the frequency synthesizer 30 is fXi (i = 1 to n), the frequency switching of the frequency synthesizer 30 can switch the transmission frequency to n. In the conventional example (FIG. 7), since the local oscillator of the loopback tester 3 is fixed, the loopback test within the local station cannot be performed at all desired frequencies. Further, in order to switch the transmission frequency to n kinds and to perform the local loopback test at all desired frequencies, the transmission local oscillator 4 of the transmission frequency converter 1 and the test signal oscillator 15 of the loopback tester 3 are provided. Both of them had to be frequency synthesizers. However, according to the transceiver according to the fourth embodiment, the local oscillator of the loopback tester 3 is used as the frequency synthesizer 3.
By setting the value to 0, the transmission frequency can be switched to n types, and the loopback test within the own station can be performed at all desired frequencies.

In the above first to fourth embodiments, the input signal to the transmission frequency converter 1 and the output signal from the reception frequency converter 2 are intermediate frequency band signals (IF signals).
It goes without saying that the same effect can be obtained even when the input / output signals are the transmission baseband signal and the reception baseband signal.

[0021]

[0022]

As described above, according to the invention described in claim 1,
According to this, one local oscillator in the radio frequency band is used, and the output of this local oscillator is used for the local oscillation wave of either the transmission frequency conversion unit or the reception frequency conversion unit, and the output of the local oscillator and the loopback tester are used. Since the output obtained by mixing with the local oscillation wave from the local oscillator of is used for the other local oscillation wave, a large and complicated RF
It is possible to reduce the number of band local oscillators, further reduce the size of the transmitter, further reduce power consumption, and further simplify the configuration.

According to the second aspect of the invention, since the operation or non-operation of the folding tester is controlled by turning on or off the local oscillation wave, it is necessary to provide an expensive high-frequency switching device. Therefore, the device can be made compact and inexpensive.

Further, according to the invention described in claim 3, above
Since the serial local oscillator is constituted by a frequency synthesizer, it is possible to arbitrarily switch the transmit or receive frequency, it is possible to perform the local station folding test at desired total frequency.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a transceiver according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an input / output frequency relationship of the transceiver according to the first embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a transceiver according to a second embodiment of the present invention.

FIG. 4 is a diagram showing an input / output frequency relationship of a transceiver according to a second embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a transceiver according to a third embodiment of the present invention.

FIG. 6 is a block diagram showing a configuration of a transceiver according to a fourth embodiment of the present invention.

FIG. 7 is a block diagram showing a configuration of a conventional transceiver.

[Explanation of symbols]

1 transmission frequency conversion unit, 2 reception frequency conversion unit, 3 folding tester, 4 transmission local oscillator, 5 mixer, 6 band pass filter, 7 transmission RF amplifier, 8 (transmission side) switch, 9 (reception side) Switch, 10 reception RF
Amplifier, 11 band pass filter, 12 receiving local oscillator, 13 mixer, 14 low pass filter, 15 test signal local oscillator, 16 mixer, 17 band pass filter, 20 mixer, 21 band pass filter, 22
Local oscillator (for RF signal), 23 mixer, 24
Bandpass filter, 25 amplifiers, 26 power lines, 2
7 Power switch, 28 Combiner (on transmitting side), 29
Combiner (on receiving side), 30 frequency synthesizer, 1S
Transmission IF signal, 2S Reception IF signal, 3S Local oscillation wave (for aliasing test), 1C Local oscillation wave (for transmission frequency conversion unit), 2C Local oscillation wave (for reception frequency conversion unit), 1W Transmission RF signal, 2W Received RF signal.

Claims (3)

(57) [Claims] 1. A transmission frequency conversion unit for frequency-converting a transmission baseband or intermediate frequency band signal into a transmission radio frequency band signal, and a reception frequency conversion for frequency conversion of a reception radio frequency band signal into a reception baseband or intermediate frequency band signal. And a loopback tester that has a local oscillator for a loopback test and frequency-converts the transmission radio frequency band signal into the reception radiofrequency band signal based on a local oscillation wave output from the local oscillator. In this machine, one local oscillator in the radio frequency band is used, and the output of this local oscillator is used for the local oscillation wave of either the transmission frequency conversion unit or the reception frequency conversion unit, and the output of the local oscillator in the radio frequency band is used. Using the output obtained by mixing the output of the local oscillator for loopback test and the local oscillation wave of the other frequency conversion unit A transceiver characterized by. Wherein the on or blocking of the local oscillation wave transceiver according to claim 1 Symbol mounting is characterized in that so as to control the operation or non-operation of the folded tester. 3. A transceiver according to claim 1, characterized by being configured by a frequency synthesizer the local oscillator.