JP2817258B2 - Control signal transmission circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal transmission device, and more particularly to a control signal transmission circuit capable of additionally transmitting 1-bit information in addition to an original transmission signal. 2. Description of the Related Art Conventionally, a signal transmission device may be required to transmit status information or a control signal of a device by adding 1-bit information in addition to an original transmission signal. In this case, conventionally, a method of transmitting a 1-bit signal by adding a new signal line has been used, or a method of transmitting information by multiplexing the 1-bit signal with an original transmission signal has been used. [Problems to be Solved by the Invention] In the above-described conventional circuit, when a new signal line is added, the signal line becomes double. Therefore, when the transmission line is long, the cable cost increases, and The above problems are likely to occur. Further, in the case of performing signal multiplexing, a filter for demultiplexing subcarriers on a frequency, or a switching device and a timing circuit for demultiplexing on a time axis are required, which complicates the circuit and increases the cost. There is a problem of mimicry. An object of the present invention is to provide a control signal transmission circuit that can easily transmit a 1-bit signal without causing these problems. [Means for Solving the Problems] A control signal transmission circuit according to the present invention includes a transmission side having two modulators and a reception side having two demodulators, and includes two working and protection transmission lines. Applies to configured signal transmission devices. That is, on the transmission side, a first amplitude modulator that amplitude-modulates the output of the modulated wave oscillator with a transmission signal, a phase shifter that shifts the output of the modulated wave oscillator by π, and adds the transmission signal to the transmission signal. A switch for selecting either the output of the modulated wave oscillator or the output of the phase shifter based on the additional information to be transmitted; and a second amplitude modulation for amplitude-modulating the output of the switch with the transmission signal. A receiver for demodulating the signals of the first and second amplitude modulators and outputting a transmission signal on the receiving side.
An amplitude demodulator, an adder for synthesizing the signals of the first and second amplitude modulators, and an identifier for identifying the level of an output of the adder to identify the additional information. [Operation] According to this configuration, the output level of the added signal on the receiving side is changed according to the switching state of the switch on the transmitting side, and the receiving side is configured based on the output level of the added signal. The state of the switch on the transmitting side can be identified, and the switch state of the switch can be transmitted as 1-bit information. Embodiment Next, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of one embodiment of the present invention. In the figure, it is assumed that a signal is transmitted from the device 1 to the device 2 now. These devices 1 and 2 are of a working or standby configuration. The device 1 has a first modulator 4 and a second modulator 5 connected to an input terminal 3.
And performs modulation with the modulated wave of the same modulated wave oscillator 6. Here, a π phase shifter 7 and a switch 8 are connected between the modulated wave oscillator 6 and the second modulator 5, and the modulated wave in the second modulator 5 is changed to a 0 phase shift wave or a π phase shift wave. You can choose to either. On the other hand, the device 2 is provided with a first demodulator 9 and a second demodulator 10, and outputs demodulated signals to signal output terminals 13 and 14, respectively. Here, an adder 11 is connected between the two demodulators 9 and 10, and a discriminator 12 for discriminating the added signal is provided so that the discrimination result is output to an additional information output terminal 15. In this configuration, it is assumed that the signal [Am] input to the input terminal 3 is amplitude-modulated and transmitted in the working and standby configurations. Assuming that cosωt is a modulated wave, the output of the first modulator 4 is
[Am cosωt]. On the other hand, the output of the second modulator 5 is π
[Am cosωt] or [Am c by the phase shifter 7 and the switch 8
os (ωt + π)] can be arbitrarily selected. A signal [Am] of the signal passing through the transmission path is output to signal output terminals 13 and 14 in first and second demodulators 9 and 10, respectively. At the same time, the signals of the first and second modulators 4 and 5 are input to the adder 11 and added, and the combined wave [Am (cosωt
+ Cos (ωt + φ)]. However, φ = 0 or π Therefore, by switching the switch 8,
Or π, and the synthesized wave is [2Am (cos
ωt)] or

[0] is obtained. As a result, if the value of the composite wave is identified by the identifier 12, it is possible to detect which of the switches 8 is selected on the transmitting side.
Therefore, the switching position of the switch 8 can be used as 1-bit information, and it is possible to output 1-bit information to the additional information output terminal 15 in addition to the original signal. This makes it possible to easily transmit 1-bit information without having to newly provide a signal line and without performing signal multiplexing. [Effects of the Invention] As described above, the present invention switches the modulated wave by the switch on the transmission side and detects the output level of the added signal on the reception side, so that the transmission-side switch on the reception side Can be identified, and the switching state of the switch can be transmitted as 1-bit information. As a result, there is no need to add a new transmission line, and it is not necessary to perform signal multiplexing, and there is an effect that additional transmission of 1-bit information can be easily realized.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram of one embodiment of the present invention. 1,2 ... device, 3 ... input terminal, 4 ... first modulator, 5
... Second modulator 6, 6 modulated wave oscillator, 7 π phase shifter, 8 switcher, 9 first demodulator, 10 second demodulator, 11 adder , 12 ... discriminator, 13, 14 ... signal output terminal, 15 ... additional information output terminal.

Claims (1)

(57) [Claims] 1. A signal transmission device comprising two working and protection transmission lines each comprising a transmitting side having two amplitude modulators and a receiving side having two amplitude demodulators. Of amplitude modulating the output of a wave oscillator with a transmission signal
An amplitude modulator, a phase shifter that shifts the output of the modulated wave oscillator by π, and an output of the modulated wave oscillator or the phase shifter based on additional information that is added to the transmission signal and transmitted. A switching unit for selecting one of the outputs, and a second amplitude modulator for amplitude-modulating the output of the switching unit with the transmission signal; and a receiving side including the first and second amplitude modulators. Two amplitude demodulators each for demodulating a signal and outputting a transmission signal; an adder for synthesizing the signals of the first and second amplitude modulators; And a discriminator that identifies the control signal.