JPH0514232A - Transmitter-receiver - Google Patents

Abstract

PURPOSE:To prevent an excessive received input at the time of a short distance communication, and to prevent a sneaking from a transmitter side to a receiver side in the same case at the time of a long distance communication. CONSTITUTION:In a transmitter 1, signals amplified by an amplifying part 11 are mixed by a mixer 12, amplified by a power amplifying part 14, and transmitted. And also, in a receiver 2, the received signal is amplified by a low noise amplifying part 21, mixed by a mixer 22, and outputted as an intermediate frequency signal. A gain control amplifying part 24 is controlled by a gain control part 25, and the intermediate frequency signal of a constant level is outputted. The gain control part 25 controls the gain of the gain control amplifying part 24 according to a received input level, and transmits a signal C indicating the received input level to an output control part 15 of the transmitter 1. The power amplifying part 14 changes a transmitted output level according to a control signal from the output control part 15. The output control part 15 controls the output level of the power amplifying part 14 to be increased or decreased according to the increase or decrease of the received input level.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission / reception device, and more particularly to a transmission / reception device for a microwave band in which a transmitter and a receiver are housed in the same housing and communicate with each other.

[0002]

2. Description of the Related Art In a conventional transmitter / receiver, a transmitter 7, a receiver 8 and a demultiplexer 3 are housed in the same housing as shown in FIG. The transmitter 7 amplifies the signal input to the input terminal 70 to a specified level by the amplification unit 71, mixes the signal from the local oscillation unit 73 with the mixer 72, and further amplifies it with the power amplification unit 74, thereby demultiplexing it. It is sent to a transmission / reception antenna (not shown) via S.

Further, the receiver 8 amplifies a signal input via the transmitting / receiving antenna and the demultiplexer 3 by the low noise amplifying section 81, mixes the signal from the local oscillating section 83 with the mixer 82, and outputs an intermediate frequency signal. Is converted into an intermediate frequency signal of a predetermined level by the AGC amplifier 84, and then output from the output terminal 80.

[0004]

In the conventional transmitter / receiver described above, the transmitter and the receiver are housed in the same housing and operate independently of each other. That is, when communication is performed by the conventional transmitting / receiving device, the transmission output level of the transmitter is the same regardless of the communication distance. Therefore, when the communication distance becomes short, the difference between the transmission output level and the reception input level becomes small, and the reception input level to the receiver becomes excessive, causing distortion.

In the case of a long distance, the reception input level becomes low and the difference between the transmission output level and the reception input level becomes large. For this reason, there is a problem in that a sneak from the transmitter side to the receiver side occurs and a predetermined D / U ratio cannot be obtained.

An object of the present invention is to prevent distortion from occurring due to excessive input during short-distance communication, and also to prevent distortion during long-distance communication.
Prevents sneaking from the transmitter side to the receiver side
It is to provide a transceiver that can maintain the / U ratio.

[0007]

The transmitting / receiving apparatus of the present invention comprises:
In a transmitter / receiver in which a transmitter and a receiver are housed in the same housing and face each other to communicate, the receiver is
And a means for generating a signal indicating a reception level by detecting a reception input level of a signal transmitted from the opposite transmitting / receiving device; the transmitter generating an output control signal in response to the signal indicating the reception level. And a means for changing the transmission output level according to the output control signal.

[0008]

The present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. Similar to the conventional transmitter / receiver shown in FIG. 2, a transmitter 1, a receiver 2 and a demultiplexer 3 are housed in the same housing. The transmitter 1 amplifies a signal input to the input terminal 10 to a specified level by the amplification unit 11, mixes the signal from the local oscillation unit 13 with the mixer 12, and then further powers the power amplification unit 14.
It is amplified by and is sent to a transmitting / receiving antenna (not shown) via the demultiplexer 3. Further, the receiver 2 receives the signal input via the transmission / reception antenna and the demultiplexer 3 from the low noise amplifier 21.
Signal from the local oscillator 23 and the mixer 22.
Are mixed and converted into an intermediate frequency signal, further converted into an intermediate frequency signal of a constant level by the gain control amplification section 24, and then output from the output terminal 20.

By the way, the power amplifier 14 of the transmitter 1 is
The output level is controlled by the output control unit 15. The gain control amplification section 24 of the receiver 2 is controlled by the gain control section 25 and always outputs an intermediate frequency signal of a constant level with respect to a change in the reception input level. Further, the gain control unit 25 sends the signal C indicating the reception input level to the output control unit 15. The output control unit 15 decreases the output level of the power amplification unit 14 as the reception input level increases, and the power control unit 1 decreases as the reception input level decreases.
The output level of 4 is controlled to increase.

By doing so, in the case of short-distance communication, the transmission / reception devices facing each other reduce the transmission output of the transmitter with respect to the increase of the reception input level.
The reception input level can be optimized so that distortion does not occur. Also, in the case of a long distance, the transmission output of the transmitter is increased with respect to the reduction of the reception input level, so the difference between the transmission output level and the reception input level is reduced, so that the transmitter side to the receiver side is reduced. It can prevent wraparound.

[0012]

As described above, according to the present invention, the transmitting and receiving devices are used mutually by providing the function of increasing or decreasing the output level of the transmitter in response to the increase or decrease of the receiving input level of the receiver. When performing communication in opposite directions, it is possible to prevent distortion due to excessive input during short-distance communication, and to prevent sneak from the transmitter side to the receiver side during long-distance communication, and to prevent a predetermined D / U. Since the ratio can be maintained, good transmission / reception can always be performed regardless of the communication distance.

[Brief description of drawings]

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

FIG. 2 is a block diagram showing an example of a conventional transmission / reception device.

[Explanation of Codes] 1 transmitter 2 receiver 14 power amplification unit 15 output control unit 25 gain control unit C signal indicating reception input level

Claims (1)

Claim: What is claimed is: 1. A transmitter / receiver in which a transmitter and a receiver are housed in the same housing and face each other to communicate.
The receiver has means for detecting a reception input level of a signal transmitted from the opposite transmitting / receiving device and generating a signal indicating the reception level; the transmitter is responsive to the signal indicating the reception level. A transmitting / receiving apparatus comprising: a unit that generates an output control signal; and a unit that changes a transmission output level according to the output control signal.