JPH02303230A - Ratio communication system - Google Patents

Abstract

PURPOSE:To prevent the degradation in the signal quality by providing a control circuit receiving a signal from a receiver in response to a reception signal level and outputting an output control signal when the level is higher than a preset level and a transmitter receiving the output control signal to control a transmission output level. CONSTITUTION:The control circuit 9 receives a signal in response to a reception level from the receiver 5 and outputs an output control signal in response to the increase in the reception level when the level is higher than the present level to the transmitter 3. The transmitter 3 receives the output control signal from the control circuit 9 to control the transmission output level in its decreasing direction. Simultaneously since similar control is implemented in an opposite station, the signal input level to the receivers 5, 6 in both stations is controlled to be at an optimum reception level set in advance. Thus, the degradation in the signal quality due to the nonlinear distortion of the receivers resulting from an excess input level to the receivers caused by the fluctuation in the radio wave propagation state is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a wireless communication system, and particularly to a wireless communication system that transmits signals in both directions using a shared transmitting and receiving antenna.

[Conventional technology]

As shown in the block diagram of an example of a conventional wireless communication system in FIG. Transmitters 3 and 4 that send signals to the station
, receivers 5 and 6 that receive signals from the opposite station, and circulators 7 and 8 that separate the transmitted signal and the received signal, and the antenna is selected so that the input level to the receiver becomes the optimum value. At the same time, an attenuator or the like is connected to the receiver input stage for adjustment.

[Problem to be solved by the invention]

In the conventional wireless communication system described above, the antenna is selected and the attenuator at the receiver input stage is adjusted so that the input level to the receiver is at an optimal value, but the radio wave propagation conditions vary greatly. This has the disadvantage that the input level to the receiver becomes excessive, and signal quality may deteriorate due to nonlinear distortion of the receiver.

[Means to solve the problem]

The wireless communication system of the present invention is a wireless communication system that uses a shared transmitting and receiving antenna to transmit signals in both directions, and a receiving system that detects a received signal level from the shared transmitting and receiving antenna and outputs a signal according to the received signal level. a control circuit that receives a signal corresponding to the received signal level from the receiver and outputs an output control signal when the level increases above a preset value; and a control circuit that receives the output control signal from the control circuit. and a transmitter that controls the transmission output level.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the wireless communication system of the present invention. In the same figure, antennas 1 and 2 for transmitting and receiving are shown.
The signals received by the respective circulators 7
．． The signal is inputted to the receiver 5°6 via 8 and received. The receivers 5 and 6 detect the signal level of the input received signal and output a signal corresponding to the received level to the control circuits 9 and 10.

The IIJ# circuit 9.10 receives a signal corresponding to the reception level from the receiver, and outputs an output control signal to the transmitters 3 and 4 when the signal increases above a preset value.

The transmitters 3 and 4 transmit transmission signals to the opposite station via the circulator 7.8 and the antennas 1 and 2 for transmitting and receiving.

If the propagation state of radio waves changes and the reception level input to the receiver 5 rises above a preset value, the control circuit 9 receives a signal from the receiver 5 according to the reception level. , outputs an output control signal to the transmitter 3 in accordance with the increase in the reception level when the received level increases above a preset value.

The transmitter 3 receives an output control signal from the control circuit 9 and performs control to reduce the transmission output level.

At the same time, similar control is performed on the opposing station side, so that the signal input levels of the receivers 5 and 6 of both stations are controlled to the preset optimal reception level.

〔Effect of the invention〕

As explained above, according to the wireless communication system of the present invention, when the reception level input to the receiver rises above a preset value, the transmission output level of the transmitter is controlled to be reduced. It is possible to prevent the quality of the signal from deteriorating due to nonlinear distortion of the receiver due to fluctuations in the radio wave propagation state and the input level to the receiver becoming excessive. Furthermore, in this case, since the output level of the transmitter is reduced, there is a synergistic effect in that non-linear distortion of the transmitter can also be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the wireless communication system of the present invention, and FIG. 2 is a block diagram showing an embodiment of the conventional wireless communication system.

1.2... Transmission and reception antenna, 3.4... Transmitter, 5.6... Receiver, 7.8... Circulator,
9゜10...control circuit.

Claims (1)

[Claims] In a wireless communication system that transmits signals in both directions using a shared transmitting and receiving antenna, there is provided a receiver that detects a received signal level from the said transmitting and receiving shared antenna and outputs a signal according to the received signal level; a control circuit that receives a signal corresponding to the received signal level and outputs an output control signal when the level increases above a preset value; and a transmitter that receives the output control signal from the control circuit and controls the transmission output level. A wireless communication system characterized by consisting of a