JPS60236333A - Radio relay system - Google Patents

Abstract

PURPOSE:To prevent the erroneous start of a transmitter which is due to a radio wave received from a peripheral radio circuit, by starting a radio transmitter to transmit the reception signal when a signal received by a radio receiver contains a subcarrier wave which is used to the data communication. CONSTITUTION:A data communication signal 9 transmitted from an end office 1 received by a radio receiver 3 within a radio relay device 6 via a radio circuit 7. The receiver 3 outputs a transmission signal 10. The signal 10 is supplied to a subcarrier wave detecting circuit 5, and a tone detecting signal 11 showing the tone detecting state is outputted from the circuit 5 when the signal 10 contains a subcarrier wave. The signal 11 is supplied to a radio transmitter 4, and the signal 10 is supplied to an end office 2 from the transmitter 4 via a radio circuit. As the signal 11 is used to start the transmitter 4, it is prevent that the transmitter 4 is started by the radio wave sent from a peripheral radio device using the same frequency.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a wireless relay system, and particularly to a wireless relay system that performs data communication using a wireless line.

(Prior Art) When making calls or data communications using a wireless line, relay stations are often installed depending on the state of radio wave propagation.

This relay station inputs and amplifies radio waves emitted from a terminal device located in one direction among the plurality of terminal devices to be transmitted, and then transmits the radio waves to other terminal stations located in a direction different from the terminal station. It enables non-line-of-sight communication by emitting radio waves.

In this way, while the relay station is receiving radio waves from one direction,
It is necessary to have a function to emit the received signal in the other direction as another radio wave, but the conventional means to achieve this function are the electric field squelch method, which transmits when the electric field level of the received radio wave is above a certain level, and the electric field squelch method, which transmits when the electric field level of the received radio wave A tone squelch method has been used in which a tone signal other than the signal to be transmitted is mixed and transmission is performed when the tone signal is received. The former tends to cause malfunctions in which the transmitter is activated by mistake when radio waves are received from other nearby wireless lines, and the latter requires special circuits for transmitting and receiving tones at all terminal stations and relay stations. However, the drawback was that the price was high.

(Object of the Invention) The present invention is capable of transmitting signals from nearby wireless lines by activating a transmitter only while a subcarrier is included in the received data communication signal when receiving radio waves from a terminal station. To provide a wireless relay system that prevents a transmitter from being erroneously activated when receiving radio waves.

(Structure of the Invention) According to the present invention, a wireless transmitter is activated while a subcarrier used for a data communication signal is included in a signal received by a wireless receiver, and the signal received by the wireless receiver is transmitted. A wireless relay system is obtained in which transmission is performed from the wireless transmitter.

(Example) Next, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention, which is a wireless relay device that receives a data communication signal 9 transmitted from one terminal station 1 via a wireless line 7 [a wireless receiver 3 in the 6 is a transmitter]. Outputs signal 10. The transmission signal 10 is input to the subcarrier detection circuit 5, and while the subcarrier is included, the open carrier detection circuit 5
A tone detection state 11 indicating the tone detection state is outputted from. The tone detection signal 11 is supplied to the radio transmitter 4, and when the tone detection signal 11 is on, the transmission signal 10 is transmitted from the radio transmitter 4 to the terminal station 2 via the radio line 8.

In this embodiment, by using the tone detection signal 11 as a condition for activating the wireless transmitter 4, if the wireless receiver 4 receives a radio wave from a nearby wireless device using the same frequency, an error occurs. This can prevent the wireless transmitter 4 from being activated.

(Effects of the Invention) As explained above, the present invention prevents a relay station wireless transmitter from entering a transmitting state due to reception of radio waves from a nearby wireless line, without adding any special functions to the terminal station. effective.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention. 1...Terminal station, 2...Terminal station, 3...
・Radio receiver, 4... Radio transmitter, 5... Subcarrier detection circuit 6... Radio relay device, 7...
・Wireless line, 8... Radio line, 9... Data communication signal, 10... Transmission signal, 11...
・・Tone detection signal

Claims (1)

[Claims] activating a wireless transmitter and transmitting the signal received by the wireless receiver from the wireless transmitter while the signal received by the wireless receiver includes a subcarrier used for a data communication signal; A wireless relay system featuring