JPS62266930A - Radio wave repeater - Google Patents

Abstract

PURPOSE:To easily and stably offset for few frequencies to which the transmission/reception signal of radio frequency is designated by providing a phase modulator as an endless phase shifter and a modulation signal oscillator to a transmission section. CONSTITUTION:A reception signal 11 received by a reception antenna 1 is converted into an intermediate frequency by a frequency converter 5 at first and amplified by an amplifier section 7. Then the signal is converted again into a radio frequency by a frequency converter 8 and subject to phase modulation by a phase modulator 20 as an endless phase shifter. In such a case, the radio frequency inputted to the modulator 20 is offset by a predetermined few frequencies. That is, assuming the frequency of the signal 11 as F0 and an output frequency of a modulation signal oscillator 21 as f, then the transmission signal frequency is F0+ f. The modulator 20 and the oscillator 21 are provided to the transmission section in such a way so as to easily and stably offset the transmission/reception signal in radio frequency by the predetermined few frequencies f.

Description

Detailed Description of the Invention (1) (Technical Field of the Invention) The present invention amplifies a radio frequency reception signal received by a reception antenna, and reproduces the transmission signal from the transmission antenna on the same radio channel as the reception signal. The present invention relates to a device configuration for slightly offsetting the frequency of transmitted and received signals in order to measure the amount of coupling between transmitting and receiving antennas in a wireless relay for transmission.

(2) (Prior art and its problems) In wireless communication, FIG. 1 shows the basic configuration of a wireless relay device that uses the same wireless channel for received signals and transmitted signals. In Figure 1, the wireless relay device is a receiving antenna 1 (gain G
+ ), branch circuit 2, detector 3, control section 4, frequency converter 5 (gain Gs), signal generator 6, amplification section 7 (channel filter 7a and amplification section 7b (gain G, )), frequency converter 8 (gain Ga), a signal generator 9, and a transmitting antenna 10 (gain G, .).

The basic operation of the radio medium equipment is to receive a received signal 11 with a receiving antenna 1, convert it to an intermediate frequency with a frequency converter 5, select a channel to be relayed with a channel filter 7a, and amplify it with an amplifier 7b. Afterwards, the frequency converter 8 converts the signal to a radio frequency again, and the transmitting antenna 10 transmits the transmitted signal 12.
It is to transmit as. The signal 11 and the signal 12 are the same radio channel, and when the radio channel to be relayed is switched, the frequency f of the signal generator 6 is changed. and the frequency f of the signal generator 9. By switching +Δf, the radio channel to be interrupted is tuned. Further, the relay device gain G is G=G, .G, .G7.G8.G. It is.

Reference numeral 13 denotes a wraparound signal of the transmission signal at the receiving antenna 1, and when the amount of transmission tS loss between the transmitting and receiving antennas is Ll+, the level of the signal 13 is 1/L, 3 times that of the signal 12. Therefore, G/L H3 is the loop gain of the loop signal. Here, when the loop gain is larger than 1 (L+z<G), the system becomes unstable and oscillates, which adversely affects the communication system. Therefore, when using a relay device, it is necessary to take into consideration the mounting of the transmitting and receiving antennas and the amplifier gain so that the amount of propagation loss L +3 between the transmitting and receiving antennas is sufficiently larger than the gain G of the relay device.

A conventional technique for measuring the amount of propagation loss between transmitting and receiving antennas for this purpose is as described in Japanese Patent Application No. 60-281219. That is, the frequency of the received signal 110 is Fo, and the frequency of the signal generator 6 is Fo. The received signal 11 is converted to an intermediate frequency by the frequency converter 5, amplified, and then converted again by the frequency converter 8 to a signal of the same radio channel as the received signal, thereby becoming the transmitted signal 12. Here, the frequency of the received signal 11 is F. Let the frequency of signal generator 9 be r
. +Δf, the frequency of the transmitted signal 12 is F0+Δ
r, and the frequency of the transmitted signal 12 is offset by Δf compared to the received signal 11. Since Δf is a low frequency of about 100 Hz, which is a small frequency compared to a radio frequency, it does not affect communication.

The received signal 11 and the loop signal 13 of the transmitted signal are input to the receiving section of the repeater, but the frequencies of the signals 11 and 13 are Δ
Since the signal is offset by f, a beat having a frequency Δr occurs in the envelope of the composite wave of the received signal 11 and the wraparound signal 13. The detector 3 detects this beat and measures the amount of wraparound of the transmitted signal from its level. The control unit 4 determines whether there is a risk of the loop gain becoming larger than 1 based on the measured value of the amount of loop gain obtained by the detector 3, and if there is a risk, the gain of the amplifier unit 7 is lowered, etc. control.

However, for example, Fo is a radio signal in the 900 MHz band with a channel spacing of 25 kHz, and if the intermediate frequency is assumed to be in the 90 MHz band, fo is 810 MHz. In order to set the frequency difference between signal generator 6 and signal generator 9 to Δf = 100Hz and keep the error of Δf within 10%, the frequency stability required for signal generators 6 and 9 is 100X0.1/(810X1
0')=1.2X10-'. Considering temperature changes in wireless relay equipment used outdoors, it is difficult to achieve the above frequency stability using individual temperature-compensated crystal oscillators, etc., and expensive, large, highly stable oscillators such as cesium oscillators are used. I needed it.

Further, FIG. 2 shows an example of a conventional synthesizer method based on the same signal oscillator. FIG. 2 shows the configuration of the signal generators 6 and 9 in FIG. 1, and the configuration and operation of other parts of the relay device are the same as in FIG. 1. 14 is a reference signal oscillator;
15 is a frequency divider.

16a, 16b are phase comparators, 17a, 17b are low pass filters, 18a, 18b are voltage controlled oscillators, 19a
.

19b is a variable frequency divider and constitutes a synthesizer, and subscripts a and b indicate two systems of signal generators 6 and 9, respectively. The reference signal oscillator 14 is an oscillator such as a temperature compensated crystal oscillator, and its output is divided by a frequency divider 15 into a frequency that is a basic unit of frequency switching of the synthesizer. The variable frequency divider 19a (19b) divides the daily output of the voltage controlled oscillator into basic unit frequencies, and the phase comparator 16a (16b)
The output frequencies of the frequency divider 15 and the variable frequency divider 19a (19b) are compared at
17b) is used as a control voltage for the voltage controlled oscillator 18a (18b) to control the synthesizer output frequency to always be correct.

In this method, the frequency difference between the signal generator 6 and the signal generator 9 is always constant, and when a frequency drift occurs in the reference signal oscillator 14, the signal generator 6 and the signal generator 9 drift while keeping the frequency difference constant. do. Therefore, the reference signal oscillator 14 does not need to be a particularly highly stable oscillator.

However, as in the above example, the FO is a wireless signal in the 900 MHz band with a channel spacing of 25 kHz, and the intermediate frequency is 90 MHz.
If the transmission/reception frequency offset is 100Hz for the Z band, the basic frequency setting unit of the synthesizer is 100Hz. In this case, the cutoff frequency of the low-pass filter 17a (17b) is several tens of Hz, and the time constant of frequency control becomes long. The drawback is that the pull-in time is long, on the order of several seconds.

(3) Object of the Invention An object of the present invention is to provide a radio relay device using a circuit that easily and stably offsets a radio frequency transmission/reception signal by a small predetermined frequency.

(4) Structure of the Invention (4-1) Features of the Invention and Differences from the Prior Art The first invention of the present application uses an infinite phase shifter in the transmitting section, operates it at an offset frequency, and offsets the transmitting and receiving radio frequency. Its main feature is to

The second invention of the present application is a baseband relay that demodulates a relay signal, modulates it again, and sends it out, and by slightly offsetting the carrier frequency during modulation from the reproduced carrier frequency during demodulation, wireless transmission and reception is achieved. The main feature is to offset the frequency.

A third invention of the present application is that the local signal of the transmitting/receiving frequency converter is configured by two signal generators based on the same oscillator, and the first signal generator is a synthesizer based on the oscillator, The second signal generator includes a first and a second synthesizer, and the first synthesizer uses the oscillator as a reference and sends its output to the M of the second synthesizer.
m signal, and the reference signal generated by the first synthesizer is transmitted and received at slightly different frequencies by slightly offsetting the frequency from the reference signal of the synthesizer of the first signal generator. The main feature is that it generates a local oscillation signal and offsets the transmitting and receiving radio frequencies.

In the conventional technology, separate local signal generators for transmission and reception are used, and the local signals for transmission and reception are slightly offset, which requires a highly stable oscillator, which has the disadvantage that the device is large and expensive. Furthermore, a method in which local oscillation signals for transmission and reception are slightly offset using a synthesizer method using the same reference oscillator has the disadvantage that the pull-in time is long when switching the frequency of the synthesizer.

On the other hand, the present invention is different in that it is possible to slightly offset the transmitting and receiving radio signal frequency stably with a simple configuration, and it is possible to switch between medium and m radio channels in a short time.

[Embodiment 1] FIG. 3 is a diagram showing a first embodiment of the present invention, in which 1 to 10 are the same as in FIG. 1, 20 is a phase modulator, and 21 is a modulation signal oscillator.

A received signal 11 received by the receiving antenna 1 is converted to an intermediate frequency by a frequency converter 5, amplified by an amplifier 7, converted to a radio frequency again by a frequency converter 8, and then phase modulated by a phase modulator 20. . Phase modulator 20 is an infinite phase shifter. With such a configuration, the RF frequency to the infinite phase shifter 20 is offset by the modulation signal frequency Δf and output. Therefore, the frequency of the received signal 110 is Fo, and the output frequency of the modulation signal oscillator 21 is Δf = 100.
When it is Hz, the transmission signal frequency is F0+Δf. As described above, according to the present invention, it is possible to slightly offset the transmitting/receiving radio signal frequency with a simple configuration and stably. It should be noted that, as in the conventional technique, the beat of the envelope due to the loop signal branched by the branch circuit 2 is detected by the detector 3, and the gain of the amplifier part 7 is controlled by the control part 4 based on the detected amount.

Furthermore, since the local signal generator 6 of the frequency converters 5 and 8 is common, the radio frequency of the signal at the output of the frequency converter is equal to the received signal 11.

Therefore, it is clear that the first embodiment of the present invention can also be applied to a wireless relay system in which frequency conversion is not performed in the amplifier section.

The phase modulator 20 is an infinite phase shifter often used in wireless communications, and since it is an important component of the present invention, a configuration example is shown in FIG. 22 is a 90° hybrid which branches the input signal into two signals having the same level and 90° different phases. 23a
, 23b are each 180" hybrid and split the input signal into two signals having the same level and 180" different phase.
24 a, 24 b, 24 c, 24 d
are variable attenuators whose attenuation amounts are changed by control signals. Although the human power of the variable attenuators 24a to 24d is at the same level, the hybrids 22 and 23a in the front stage.

The phase is advanced by 23b, and with reference to the input signal of 22, 24a is O゛, 24b is 180°, 24C is 90°, 2
4d is input with a signal whose phase is advanced by 270 degrees. 25 is a four-man power combiner that combines each input in phase.

26 a, 26 b, 26 c, 26 d
are phase shifters and output the low frequency output of the modulation signal oscillator 21, 26a is 0°, 26b is 180゛, 26c is 90'',
26d advances the phase by 270°. Phase shifter 26a
, 26b, 26c, and 26d are connected to the variable attenuator 24.
a, 24b, 24c, 24d, respectively, 26a is 24a, 26b is 24b
, 26C is a control signal for 24C, and 26d is a control signal for 24d.

FIG. 5 shows vectors in the four-man power combiner 25 with this circuit configuration. The output vectors of 24a and 24b are 0°-18
They are on the 0° axis, have opposite phases, and their resultant vector is O
The output vectors of 240 and 24d are on the axis of 90'-270'', and their phase is opposite to each other, and their resultant vector is on the axis of 90°-270°. Although it is a simple harmonic motion, the phase of the output composite vector of 24a and 24b is shifted by 90''.Therefore, the phase modulator 20 becomes an infinite phase shifter, and the composite vector in the four-power combiner 25 is the output of the modulation signal oscillator 21. The signal rotates once on the circumference for each cycle of the signal, and the amount of phase shift is equal to the amount of phase shift of the modulation signal oscillator 21.

With this configuration, if the frequency of the received signal 11 is Fo and the output frequency of the modulation signal oscillator 21 is Δf=100Hz, the transmitted signal frequency becomes F0+Δf.

As described above, according to the present invention, it is possible to directly shift the frequency of a radio frequency transmission signal.

[Embodiment 2] FIG. 6 is a diagram showing a second embodiment of the present invention, in which 1 to 10 are the same as above, 27 is a demodulator, 28 is a baseband amplifier, and 29 is a modulator. 30 is a modulating local oscillator made of CO or the like, and 31 is a phase comparator.

A signal received by the receiving antenna 1 is converted by the frequency converter 5 to an intermediate frequency of f+y=455 kHz, for example. Next, it is demodulated to the baseband by the demodulator 27 and amplified by the baseband amplifier 28, and then returned to the intermediate frequency by modulating the output of the modulating local oscillator 30 by the modulator 29 and amplified by the amplifier 7. The signal is converted back to a radio frequency by the frequency converter 8, and is transmitted from the transmit antenna 10 as a transmit signal.

Here, the demodulator 27 is a synchronous detection type demodulator, and the amplifier 28
The baseband demodulated output is applied to the frequency f
The 1F carrier wave is regenerated and supplied to the phase comparator 31. The output of the modulation local oscillator 30 and the recovered carrier wave are input to the phase comparator 31, and the modulation local oscillator 30 is inputted by the output of the phase comparator 31 so that the frequency difference between them is equal to Δf.
control. Therefore, the carrier frequency of the output of the modulator 29 becomes flF+Δf, and the radio frequency for transmission and reception can be shifted slightly. Further, since the signal generator 6 serving as a local oscillator for the frequency converters 5 and 8 is common, the difference in signal frequency between transmission and reception does not change due to drift of the signal generator 6. Note that when the demodulator is used for something other than synchronous detection, such as frequency detection or delayed detection, it is necessary to separately provide carrier wave regeneration means.

[Embodiment 3] FIG. 7 is a diagram illustrating a third embodiment of the present invention, showing the configuration of the signal generator 6 and the signal generator 9 in FIG. 1, and other parts of the relay device. The configuration and operation of is shown in Figure 1.
is equal to A signal oscillator 32 is a temperature compensated crystal oscillator or the like. 33 is a frequency divider, 34 is a phase comparator, 35 is a low-pass filter, 36 is a voltage-controlled vibrator, 37 is a frequency divider, 38 is a frequency divider, 39 is a phase comparator, 40 is a low-pass filter, 41 is a Voltage controlled keepsake, 42 is frequency divider, 43
44 is a phase comparator, 45 is a low-pass filter, 46 is a voltage-controlled vibrator, and 47 is a frequency divider.

The signal generator 6 in FIG. 1 is a synthesizer composed of 34, 35, 36, 37, and the signal generator 9 is a
The first synthesizer consists of 40.41.42.43 and the second synthesizer consists of 44.45.46.47.

The signal oscillator 32 is a reference for two systems of signal generators, and is, for example, a 10 MHz temperature compensated crystal oscillator whose frequency is divided by a frequency divider 33 to obtain a 25 kHz signal. This signal becomes a reference signal for the synthesizer constituting the signal generator 6, and has a frequency equal to the radio channel spacing.

The output f0 of the voltage-controlled keepsake device 36 is a signal in the 800 MHz band and is a local signal of the frequency converter 5. Signal generation H
The type of synthesizer that constitutes 6 is used in 900 MHz band car telephone systems, etc., and the time required to switch channels is several tens of milliseconds.

The output of the signal oscillator 32 is divided by a frequency divider 38 to 10
Obtain a 0Hz signal. This signal becomes a reference signal for a first synthesizer forming a component of the signal generator 9. The output of the voltage-controlled vibrator 41 is a 109+100Hz signal, which is divided by the frequency divider 43 to 25X 10'.
+ (1/400) Hz signal is obtained, and this signal is used as a reference signal for the second synthesizer. The configuration of the second synthesizer is the same as that of the synthesizer constituting the signal generator 6.

Therefore, the output of the signal generator 9 has a frequency shifted by about 100 Hz compared to the output of the signal generator 6.

In this configuration, since the reference signal of the first synthesizer constituting the signal generator 9 is as low as 100 Hz, it takes several seconds for the first synthesizer to stabilize. However, the first synthesizer is set only when the wireless repeater is powered on, and the output frequency of the first synthesizer is not changed thereafter. When switching the radio channel to be relayed, the synthesizer making up the signal generator 6 and the second synthesizer making up the signal generator 9 are switched, and the pull-in time is several tens of milliseconds.

(5) (Effects of the Invention) As explained above, according to the present invention, it is possible to easily and stably shift the transmitting/receiving signal frequency of a wireless relay device by a small amount of frequency.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram according to the prior art of a wireless relay device that uses the same radio channel for the received signal and the transmitted signal, FIG. 2 is a block diagram showing an example of a synthesizer method according to the prior art, and FIG. 3 is a first embodiment of the present invention. FIG. 4 is a block diagram showing a configuration example of an infinite phase shifter used in the present invention. FIG. 5 is a vector diagram for explaining the operation of the infinite phase shifter. FIG. 6 is a second embodiment of the present invention. Block Diagram Showing an Example FIG. 7 is a block diagram showing an example configuration of a signal generator used in a third embodiment of the present invention. 1... Receiving antenna, 2... Branch circuit, 3...
~Detector, 4...Control unit, 5...Frequency converter, 6...Signal generator, 7...Amplification unit, 7a...
Channel filter, 7b... Amplification unit, 8... Frequency converter, 9... Signal generator, 10... Transmission antenna, 11... Reception signal, 12... Transmission signal,
13... Loop signal, 14... Reference signal oscillator, 15... Frequency divider, 16a, 16b -...
Phase comparator, 17a, 17b...Low pass filter, 18a, 18b...Voltage controlled oscillator, 19
a, 19b... variable frequency divider, 20... phase modulator, 21... modulation signal oscillator, 22... 90° high print, 23a, 23 b...=180° hybrid, 24a, 24b. 24C, 24d... variable attenuator, 25... 4 manual combiner, 26a, 26b, 26c, 26d... phase shifter, 27-... demodulator, 28... baseband amplifier, 29. ... Modulator, 30 ... Modulation local oscillator, 31 ... Phase comparator, 32 ... Signal oscillator,
33... Frequency divider, 34... Phase comparator, 35.
...Low pass filter, 36...Voltage controlled oscillator, 37... Frequency divider, 38... Frequency divider. 39... Phase comparator, 40... Low pass filter, 41... Voltage controlled oscillator, 42... Frequency divider,
43... Frequency divider, 44... Phase comparator, 45.
...Low pass filter, 46...Voltage controlled oscillator, 47... Frequency divider.

Claims (3)

[Claims] (1) Receive a radio frequency reception signal with a reception antenna,
After being amplified by an amplifier, when the transmitted signal is retransmitted from a transmitting antenna on the same radio channel as the received signal, the frequency of the transmitted signal is slightly offset from the frequency of the received signal, so that the frequency of the transmitted signal is slightly offset from the frequency of the received signal. In a radio relay device having a function of measuring the amount of radio waves looping between the transmitting antenna and the receiving antenna by detecting the amount of signal components of the offset frequency, the transmitting signal is modulated at a constant frequency using an infinite phase shifter. A radio relay device characterized in that it is configured to perform phase modulation with a signal and offset the frequency of the transmitted signal from the received signal. (2) Receive a radio frequency reception signal with a reception antenna,
After being amplified by an amplifier, when the transmitted signal is retransmitted from a transmitting antenna on the same radio channel as the received signal, the frequency of the transmitted signal is slightly offset from the frequency of the received signal, so that the frequency of the transmitted signal is slightly offset from the frequency of the received signal. In a radio relay device having a function of measuring the amount of radio waves looping between the transmitting antenna and the receiving antenna by detecting the amount of signal components of the offset frequency, the received signal is converted into an intermediate frequency signal using a local signal. converting and demodulating the carrier wave, regenerating the carrier wave, using the carrier wave as a reference signal, modulating a second carrier wave whose frequency is slightly offset with the demodulated signal, and using the local signal to convert the intermediate frequency signal into a radio frequency signal. A radio relay device characterized in that the radio relay device is configured to offset the frequency of the transmitted signal from the received signal by converting the frequency of the transmitted signal into the transmitted signal. (3) Receive the radio frequency reception signal with the reception antenna,
After being amplified by an amplifier, when the transmitted signal is retransmitted from a transmitting antenna on the same radio channel as the received signal, the frequency of the transmitted signal is slightly offset from the frequency of the received signal, so that the frequency of the transmitted signal is slightly offset from the frequency of the received signal. In a radio relay device having a function of measuring the amount of radio waves looping between the transmitting antenna and the receiving antenna by detecting the amount of signal components of the offset frequency, two signal generators based on the same oscillator are provided. , the first signal generator is configured by a synthesizer using the oscillator as a reference, the second signal generator is configured by first and second synthesizers, and the first synthesizer is configured by using the oscillator as a reference. The output of the reference signal is used as a reference signal of the second synthesizer, and the reference signal generated by the first synthesizer has a frequency slightly offset from the reference signal of the synthesizer of the first signal generator. By letting
generating first and second local signals with slightly different frequencies by the two signal generators, converting the received signal into an intermediate frequency by using the first local signal as a receiving side local oscillation signal; A radio characterized in that the frequency of the transmitted signal is offset from the received signal by converting the intermediate frequency signal into the frequency of the transmitted signal using a second local signal as a transmitting side local oscillation signal. Relay device.