JP3043656B2 - Booster relay device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a booster repeater for radio relay, and more particularly to a multiplexed signal used in a mobile communication system, for example, a plurality of Fs having different carrier frequencies.
The present invention relates to a booster relay device for simultaneously amplifying and relaying M signals.

[0002]

2. Description of the Related Art A booster repeater of this type maintains a good reception condition of radio waves up to a remote place in a radio communication field using radio frequencies such as mobile communication such as a pager and a train radio. Therefore, a radio frequency signal received by the receiving antenna is amplified and transmitted from the transmitting antenna at the same frequency as the received radio frequency signal. This is a so-called radio relay booster amplifier.

The general circuit configuration of this type of booster amplifier is composed of a receiving antenna, an amplifier, and a transmitting antenna. After a receiving signal received by the receiving antenna is amplified by the amplifier, the signal is transmitted from the transmitting antenna to the radio as a transmitting signal. To be transmitted. In this wireless relay booster amplifier, the frequency of the reception signal and the transmission signal is the same,
When the gain of the receiving antenna is G ₁ , the gain of the amplifier is G ₂ , and the gain of the transmitting antenna is G ₃ , the relay gain G is represented by G = G ₁ × G ₂ × G ₃ . Also, assuming that the propagation loss between the transmitting antenna and the receiving antenna is L, L <G
Then, there is a problem that an oscillation phenomenon occurs.

[0004] Also, since the reception level from the reception antenna fluctuates in mobile communication, there is a problem that the antenna transmission level must be stabilized against this fluctuation.
There is a conventional example described in Japanese Patent Publication No. 711.

FIG. 3 is a block diagram showing this conventional example. In FIG. 3, a signal received by a receiving antenna 40 is introduced into an input terminal of an amplifier 43 via variable attenuators 41 and 42 constituting a gain control unit. Through the transmission antenna 55. In this case, a partial signal is branched from the output signal of the amplifier 43 as the main signal in the demultiplexer 44,
The branched signal is output via a detector 45 to an output signal V _det.
AGC (Automatic GainCont)
(roll) It is introduced to the negative input terminals of the comparators 49 and 54 constituting the loop control circuit 46 and the oscillation stop circuit 47.

The positive input terminals of the comparators 49 and 54 have reference voltages V _R1 and V _R1 from reference voltage generators 50 and 53, respectively.
_R2 is introduced, and comparators 49 and 54 are provided according to the voltage difference between the output signal V _det of the detector 45 and the reference voltages V _R1 and V _R2.
Output terminals are respectively provided with a voltage signal V as an analog signal.
_C1 and a voltage signal V _C2 as a pulse signal are generated.

[0007] The output signal V _C1 of the comparator 49 is converted into an attenuation control signal V _A1 by the attenuation controller 48 and then introduced into the attenuation control terminal AT 1 of the variable attenuator 42. On the other hand, based on the output signal V _C2 of the comparator 54, the oscillation determination unit 52
It is determined whether or not the wireless relay booster amplifier is oscillating, and a determination signal V _C2 is introduced from the oscillation determining unit 52 to the attenuation controller 51 based on the determination result. Attenuation controller 51 generates the attenuation control signal V _A2 based on the judgment signal V _D2, and supplies the attenuation control terminal AT2 of the variable attenuator 41. The variable attenuator 41 outputs the attenuation control signal V
_The amount of attenuation is controlled according to _A2 .

The AGC loop control circuit 46, which is directly related to the present invention, receives the output signal V _det of the detector 45, compares it with a reference voltage V _R1 by a comparator 49, and compares the difference voltage with the output signal V _C1. Then, the attenuation of the variable attenuator 42 is varied via the attenuation controller 48 to stabilize the output signal level to a predetermined value with respect to the input signal level fluctuation.

[0009]

As described above, in the conventional example, the output level is detected in order to stabilize the output level with respect to the fluctuation of the input level, and the output level is stabilized by AGC control. Is a plurality of signals having different frequencies, that is, a frequency multiplexed signal, there is a problem that the output level per signal fluctuates due to the increase or decrease in the number of signals. That is, in the case of this kind of multiplexed signal, when the number of signals increases or decreases due to the amount of communication at that time, the output level of the total number of signals is detected and stabilized, so that the output level per signal fluctuates. .

Further, if the output level per signal is to be stabilized using this amplifier, the following problem occurs. Generally, the saturation power of the amplifier is set for the maximum output level, so the saturation power is set for the total output level when the number of signals is the maximum. However, when the output level per signal is stabilized, the total output level fluctuates according to the number of signals, and when the number of signals decreases, the output level decreases while the saturation power or power consumption is constant, resulting in lower power efficiency. There is a problem of doing it. Generally, this type of amplifier performs class A amplification with good linearity in order to suppress the occurrence of intermodulation distortion, and has low power efficiency and large power consumption. On the other hand, in this type of relay device, power saving is demanded as much as possible due to the situation of the power supply in the office building.

[0011]

A booster repeater according to the present invention comprises: a branching unit for branching a reception signal, in which a plurality of radio frequency signals having different frequencies received by a reception antenna are multiplexed, by the number of the radio frequency signals; A plurality of first output units each of which modulates a branch output signal of the branch unit with a local oscillation signal corresponding to the radio frequency signal and converts the signal to the same intermediate frequency.
A frequency conversion unit, a plurality of band-pass filters for inputting output signals of the first frequency conversion unit, removing unnecessary waves, and outputting the signals, and an output signal corresponding to the band-pass filter. A plurality of second frequency conversion units each of which is modulated by a local oscillation signal and converted into a frequency of the radio frequency signal;
A common amplifier having a synthesizing unit for synthesizing an output signal of each of the second frequency converting units, a saturation power variable unit for amplifying an output signal of the synthesizing unit and outputting the signal to a transmission antenna;
A signal number detection unit that monitors the output signal of the frequency conversion unit and detects the number of the received radio frequency signals, and controls the saturation power variable unit of the common amplifier with the output signal of the signal number detection unit to control the number of signals. And a saturation power control unit that outputs a control signal for setting an optimum saturation power corresponding to the above.

Further, a plurality of amplitude limiters for limiting the amplitude of the output signal may be inserted at the output side of each of the second frequency converters.

[0013] Alternatively, a common amplifier having a saturation power variable section for amplifying a reception signal in which a plurality of radio frequency signals of different frequencies received by a reception antenna are multiplexed and outputting the amplified signal to a transmission antenna; A plurality of branching units, a plurality of frequency conversion units that respectively modulate a branch output signal of the branching unit with a local oscillation signal of a corresponding frequency and convert the same into the same intermediate frequency, and output signals of the frequency conversion unit. A plurality of bandpass filters each for selecting an intermediate frequency, a signal number detection unit for monitoring the output signal of each bandpass filter and detecting the number of received FM signals, and an output signal of the signal number detection unit. The common power amplifier may further include a saturation power control unit that controls a saturation power variable unit and outputs a control signal for setting an optimum saturation power corresponding to the number of signals.

An output level detector for detecting the level of the output signal of the common amplifier, and the output level of the common amplifier is determined by the output signal of the output level detector and the output signal of the signal number detector. The common amplifier may include a gain control unit that outputs a control signal for controlling the gain to an optimum level corresponding to the control signal to the common amplifier, and the gain variable unit that changes a gain according to the control signal.

For example, in the common amplifier, the output stage amplifier circuit may be a class A amplifier, and the saturation power varying unit may vary the operating point of the output stage amplifier circuit according to the control signal.

[0016]

Embodiments of the present invention will now be described with reference to the drawings.

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

The booster repeater of the present invention inputs a received signal obtained by multiplexing eight FM signal waves having different carrier frequencies from the receiving antenna, equalizes the level of each signal, amplifies the level to a predetermined output level, and transmits the signal to the transmitting antenna. The saturation power of the amplifier is varied according to the number of signals.

In FIG. 1, the present booster repeater converts a received signal received by a receiving antenna into an 8
A branching unit 1 for branching, eight frequency converting units 2a to 2h for modulating respective branch output signals of the branching unit 1 with output signals of a local oscillator 6 corresponding to FM signals and converting the same to the same intermediate frequency, Eight band-pass filters 3a to 3h for inputting output signals of the converter 2 and removing unnecessary waves and outputting the signals, and output signals of the local oscillator 6 corresponding to the output signals of the band-pass filters 3 Eight frequency converters 4 for modulating each of the signals and converting them to the frequency of the original FM signal
a to 4h, amplitude limiters 5a to 5h for equalizing the level of the output signal of each frequency converter 5, a synthesizing unit 8 for synthesizing the output signals of each amplitude limiter 5, and an output signal of the synthesizing unit 8. A common amplifier 9 having a saturated power variable section for amplifying and outputting the signal to the transmitting antenna; and a signal number detecting section 10 for monitoring the output signal of each frequency converting section 4 and detecting the number of received FM signals.
And a saturation power control unit 11 for controlling the saturation power variable unit 91 of the common amplifier 9 with the output signal of the signal number detection unit 10 and setting an optimum saturation power corresponding to the number of signals.

Next, the operation will be described. The reception signal from the reception antenna is divided into eight by the branching unit 1, and is input to the frequency conversion units 2a to 2h, respectively, and modulated by the output signals of the local oscillators 6a to 6h corresponding to the frequency of each FM signal. The FM signal is converted to the same intermediate frequency band in the low frequency band. Next, the signal passes through the band-pass filter 3 and is band-limited, and unnecessary waves outside the band are removed to improve C / N.
Each FM signal in the intermediate frequency band is then converted to the original radio frequency band by the frequency converter 4, the level of each FM signal is equalized by the next amplitude limiter 5, and multiplexed by the synthesizer 8. . Each FM signal whose C / N is improved by the band limitation and whose level is equalized by the amplitude limitation is simultaneously amplified to a predetermined level by the common amplifier 9 and output to the transmitting antenna.

On the other hand, the level of the output signal of each amplitude limiter 5 is monitored by a signal number detection circuit 10, where the number of input signals is detected by level detection. The detection signal indicating the number of signals is input to the saturation power control unit 11, where a control signal for setting the saturation power of the common amplification unit 9 is generated according to the number of signals, and the saturation power variable unit 91 of the common amplifier 9 is generated.
Output to The saturation power variable section 91 sets the saturation power by changing the bias and the like of the output stage constituting the class A amplifier circuit according to the control signal.

Next, another embodiment will be described with reference to FIG. FIG. 2 is a block diagram showing another embodiment. 2, the booster repeater includes a common amplifier 27 having a saturation power variable section 271 and a gain variable section 272 for amplifying a received signal received by a receiving antenna and outputting the amplified signal to the transmitting antenna, and a common amplifier 24 for amplifying the received signal. Branching unit 21 that branches to the number of FM signals at the same time with low loss
Eight frequency converters 23a to 23h for respectively modulating the branch output signals of the branch unit 21 with the output signals of the local oscillators 27a to 27h having the frequencies corresponding to the FM signals and converting the same to the same intermediate frequency; Eight band-pass filters 24a to 24h each for selecting an intermediate frequency from the output signal of the unit 23, and a signal number detecting unit 25 for monitoring the output signal of each band filter 24 and detecting the number of received FM signals. And the common amplifier 2 based on the output signal of the signal number detector 25.
Saturation power control unit 26 for controlling the saturation power variable unit 221 and setting the optimum saturation power 2 corresponding to the number of signals
And an output level detector 28 for detecting the level of the output signal of the common amplifier 22, and the output level of the common amplifier 22 corresponds to the number of signals from the output signal of the output level detector 28 and the output signal of the signal number detector 25. And a gain control section 29 for outputting a control signal for controlling the gain to the optimum level to the gain variable section 22 of the common amplifier 22.

Next, the operation will be described. The reception signal from the reception antenna is directed to the common amplification unit 22 by the branch unit 21,
The branching is performed in eight directions. The branching in the direction of the common amplifier 22 has a small branching loss and reduces the influence on the main signal. 8
Each of the branched received signals is converted by the frequency converter 23 into the local oscillator 2.
7 and converted to the same intermediate frequency at a low frequency. Each FM signal converted to the intermediate frequency is subjected to a band-pass filter 24 to remove unnecessary waves, and is input to a signal number detection unit 25, respectively. The bandpass filter 24 may be a simple one capable of level detection. The signal number detector 25 confirms the input of each FM signal by level detection and detects the number of received FM signals. The detection signal indicating the number of signals is input to the saturation power control unit 26, where it is converted into a control signal and output to the saturation power variable unit of the common amplifier. This control signal sets the saturation power of the common amplifier 22 as described with reference to FIG.

On the other hand, a part of the output signal of the common amplifying unit 22 is input to the output level detecting unit 28, where the output level value is detected, and the detection signal indicating the output level value is sent to the gain control unit 29. Output. The gain control unit 28 receives the detection signal of the output level detection unit 28 and the detection signal of the signal number detection unit 25, calculates the output level of the common amplification unit 22 corresponding to the number of signals, and determines that the output level is constant. The gain control signal for controlling the gain is output to the gain variable section 222 of the common amplifying section 22. The gain variable section 222 does not change the gain with the gain control signal with respect to the increase or decrease of the number of signals, but adjusts only the change of the input level.

That is, as described above, the common amplifier 22
The optimum saturation power and output level are automatically set according to the number of input FM signals.

The booster repeater shown in FIG. 2 has a drawback that when the input level of each FM signal varies in stabilizing the output level, it cannot be equalized as compared with the booster relay apparatus shown in FIG. Since the number detection part can be simplified, there is a feature that the cost can be reduced and the size can be reduced.

Further, the oscillation stop circuit described with reference to FIG. 3 may be added to the booster repeater shown in FIGS.

[0028]

As described above, the booster repeater of the present invention stabilizes the output level of each radio frequency signal and automatically sets the saturation power corresponding to the number of signals. The output level per signal does not fluctuate according to the number, and the saturation power is set in accordance with the number of signals. Therefore, when the number of signals decreases, the power consumption is reduced and the power efficiency is not deteriorated. is there. In particular, in the embodiment shown in FIG. 1, since the band limitation and the amplitude control are performed for each signal, the power efficiency is improved and the C / C ratio is improved.
There is an effect that N can be improved and the level of each signal can be made uniform.

[Brief description of the drawings]

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

FIG. 2 is a block diagram showing another embodiment of the present invention.

FIG. 3 is a block diagram showing a conventional example.

[Explanation of symbols]

1, 21 branch unit 2a to 2h, 4a to 4h, 23a to 23h frequency conversion unit 3a to 3h band-pass filter 5a to 5h amplitude limiter 8 synthesis unit 9, 22, common amplifier 6a to 6h, 27a to 27b local oscillator 10 , 25 signal number detection section 11, 26 saturation power control section 28 output level detection section 29 gain control section

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H03G 3/20-3/34 H03F 1/02 H04B 7/15 H04B 7/26

Claims (5)

(57) [Claims] 1. A branching unit for branching a reception signal in which a plurality of radio frequency signals having different frequencies received by a reception antenna are multiplexed into a plurality of radio frequency signals, and a branch output signal of the branching unit being transmitted to the radio unit. A plurality of first frequency converters each of which is modulated by a local oscillation signal corresponding to a frequency signal and converted into the same intermediate frequency; and an output signal of the first frequency converter is input, and unnecessary waves are removed and output. A plurality of bandpass filters for band limiting, and a plurality of second frequency conversion units for respectively modulating the output signal of the bandpass filter with the corresponding local oscillation signal and converting it to the frequency of the radio frequency signal, A common amplifier having a synthesizing unit for synthesizing an output signal of the second frequency conversion unit, a saturation power variable unit for amplifying an output signal of the synthesizing unit and outputting the signal to a transmission antenna; A signal number detection unit that monitors the output signal of the unit and detects the number of the received radio frequency signals, and controls the saturation power variable unit of the common amplifier with the output signal of the signal number detection unit to correspond to the number of signals. A booster relay device comprising: a saturation power control unit that outputs a control signal for setting an optimum saturation power. 2. The booster repeater according to claim 1, wherein a plurality of amplitude limiters for limiting the amplitude of the output signal are inserted on the output side of each of said second frequency converters. 3. A common amplifier having a variable saturation power section for amplifying a reception signal in which a plurality of radio frequency signals of different frequencies received by a reception antenna are multiplexed and outputting the amplified signal to a transmission antenna, A branch unit that branches into a number of signals, a plurality of frequency conversion units that respectively modulate a branch output signal of the branch unit with a local oscillation signal of a corresponding frequency and convert the same to the same intermediate frequency, and an output signal of the frequency conversion unit A plurality of bandpass filters for selecting an intermediate frequency from each, a signal number detection unit for monitoring the output signal of each of the bandpass filters and detecting the number of received radio frequency signals, and an output of the signal number detection unit A saturation power control unit that controls a saturation power variable unit of the common amplifier with a signal and outputs a control signal for setting an optimum saturation power corresponding to the number of signals. Booster relay device. 4. An output level detector for detecting a level of an output signal of the common amplifier, and an output level of the common amplifier is determined based on an output signal of the output level detector and an output signal of the signal number detector. 2. A gain control unit for outputting a control signal for controlling to an optimum level corresponding to the control signal to the common amplifier, and the common amplifier includes a gain variable unit for changing a gain by the control signal. Alternatively, the booster relay device according to 3. 5. The common amplifier according to claim 1, wherein the output stage amplifying circuit is a class A amplifier, and the saturation power varying section varies an operating point of the output stage amplifying circuit by the control signal. 5. The booster relay device according to 3 or 4.