JPS59141838A - Analog signal transmission system containing level setting function of transmission signal - Google Patents

Abstract

PURPOSE:To set quickly and easily the level of a transmission signal by actuating a signal oscillator at the transmission side with use of a control signal. CONSTITUTION:Optical transmitting/receiving devices 10 and 10' are connected via an optical fiber 6, and switches SW1 and SW3 are applied to set the device 10 in a test mode. Then the control signal is delivered from a control signal transmitting part 11. This control signal is transmitted to a control signal receiving part 12' of the device 10' through an optical transmitter 2, an optical branching device 3 and an optical fiber. The part 12' identifies the control signal and then drives an oscillator 15' to turn on a switch SW2'. The output of the oscillator 15' is sent to the device 10 via the fiber 6 and turns on a lamp 16 when level detector 14 detects a prescribed level of the signal. If the signal is not set at the prescribed level, a level control variable resistor VR1 sets again the level of the transmission signal.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an analog signal transmission system that is equipped with a level setting function that can easily set the transmission signal level in a short time in an analog signal transmission system that performs bidirectional signal transmission.

FIG. 1 is a block diagram showing a conventional optical transceiver. An analog signal transmission system will be explained using an example of an optical transceiver that performs bidirectional transmission using optical fiber. Each optical transceiver 1 includes an optical transmitter 2, an optical splitter 3, an optical receiver 4, and an amplifier 5.
and are connected to each other by optical fibers 6 to transmit and receive optical signals. This optical transmitter/receiver 1 needs to have an input/output level of a signal to be transmitted within a certain range, and usually the receiver side is provided with a level adjustment function in order to set the output level to a specified level. When performing this level adjustment, a signal generator is connected to the input on the transmitting side, and a level meter is connected to the output on the receiving side, and communication is made between the two points. There are disadvantages such as the need to go back and forth between the two points to adjust the level, the need to prepare a measuring device, and the need to go back and forth between two points, which is time consuming and inefficient.

SUMMARY OF THE INVENTION An object of the present invention is to provide an analog signal transmission system equipped with a level setting function that enables smooth setting of the level of a transmitted analog signal in a short time in an analog signal transmission system that performs bidirectional signal transmission. be.

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

FIG. 2 is a block diagram showing an embodiment of the analog signal transmission system of the present invention. The analog signal transmission system will be explained using an example of an optical transceiver as in FIG. 1. Although the optical transceiver 10 and the optical transceiver 10' are exactly the same, they are given different symbols for convenience of explanation. The optical transceiver of the present invention has a signal level setting function as described below, and eliminates the troublesome level setting in conventional optical transceivers, making it possible to smoothly adjust the level in a short time. Referring to FIG. 2, a case will be described in which level adjustment is performed from the optical transceiver al:10' to the optical transceiver 10 on the optical transceiver 10 side.

First, the optical transceivers 10 and 10' are connected by the optical fiber 6, and both optical transceivers are turned on.

Next, the switch SW3 is turned on to put the optical transceiver 10 into the test mode, and the control signal transmitter 11 sends out a control signal, and the switch SWI is turned to the test side. The control signal is transmitted via the switch SW1, the optical transmitter 2, the optical splitter 3, and the optical fiber 6, and is further transmitted to the optical splitter 3', the optical receiver 4', and the low-pass filter 13' of the optical transceiver 10'. The signal reaches the control signal receiving section 12' via the control signal receiving section 12'. Control signal receiving section 1
After 2' identifies the received signal as a control signal, oscillator 15' is activated to generate an output signal and switch S
W2' is turned on. The output signal from this oscillator 15' is transmitted to the optical branch 3 of the optical transceiver 10 via the switch sW2', the optical transmitter 2', the optical branch 3', and the optical fiber 6.
The light reaches the level detection section 14 via the optical receiver 4. The level detection unit 14 detects the transmitted signal and converts it into direct current, and compares the level of the converted signal with a window comparator to see if it is within a predetermined level range. The lamp 16 is turned on. Therefore, the variable resistor VRI for adjusting the level of the optical transceiver 100 is connected to the lamp 1.
If the switch 6 is turned until it lights up, the signal transmission level of the optical transceiver 1° will be set.

Note that the signal injected from the oscillator 15.15' to the optical transmitter 1.1' is injected at the same frequency and level as the normally transmitted signal. The same explanation can be given to the case where the level adjustment of the optical transceiver 10' is performed from the optical transceiver 10. Furthermore, although an optical transceiver that transmits an analog optical signal through an optical fiber has been described, the present invention is also applicable to transmitting an analog electrical signal.

As described above, according to the present invention, the transmission signal level of an analog signal transmission system that performs bidirectional signal transmission can be increased to 1 without the need to separately prepare a signal generator and a level meter.
The effect can be easily set by a person in a short time.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a conventional optical transceiver, and FIG. 2 is a block diagram showing an embodiment of the analog signal transmission system of the present invention. 1.10.10': Optical transceiver 2: Optical transmitter 3: Optical splitter 4: Optical receiver 6: Optical fiber 11.11': Control signal transmitter 12.12': Control signal receiver 13.13 ': Low-pass filter 14.14'2 Level detection section 15.15': Oscillator 16.16'2 Lamp Patent applicant Sumitomo Electric Industries, Ltd. (4 others)

Claims (1)

[Scope of Claims] (1) In an analog signal transmission system consisting of a plurality of bidirectional analog signal transceivers that require level adjustment of a transmitted signal before signal transmission, each transceiver has a predetermined level and frequency control function. control signal transmitting means for generating a signal, control signal receiving means for determining whether a received signal is a control signal, and generating an output signal of a predetermined level driven by the output from the receiving means in response to reception of the control signal. one transceiver, comprising: an oscillator that detects the level of the output signal; a level detection means that detects the level of the output signal; and a level adjustment means that adjusts the control signal until the signal detected by the level detection means reaches a predetermined level. sends a control signal to the other transceiver and drives the other oscillator via the control signal receiving means to generate an output signal at a level corresponding to the transmission signal level; one level detecting means detects the output signal. An analog signal transmission system equipped with a transmission signal level setting function characterized in that the output level of one transmitter/receiver is set to a predetermined signal level by one level adjustment means without detection. (2. Claim 1, wherein the analog signal transmitter/receiver is an optical transmitter/receiver. (3) Claim 1: 2. The analog signal transmission system according to claim 1, wherein the frequency and level of the oscillator match the frequency and level of the transmission signal.