JPS6249771B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tally detection device for detecting tally signals in a signal switching device.

In a signal switching device that switches between a plurality of input signals and selects one signal, an indicator is required to indicate the selected signal in order to detect the selected signal. In conventional switching devices, an indicator such as a lamp is built into the push button to detect the selected signal, and when the button is pressed for switching, the contact is directly closed and turned on, or the switching circuit is activated. The switching circuit was controlled by a flip-flop circuit to hold the included control voltage, and this voltage was obtained to light lamps and the like as a tally.

FIG. 1 is a diagram showing the configuration of a conventional tally detection circuit.
When pressed and grounded, timing pulse 1 that determines the timing of switching is applied to gate circuits 41 and 4.
Pass through one of 2,43 and flip flop 5
1, 52, 53, and the switching circuit 6
One of 1, 62, and 63 is held on. As a result, one of the input signals 31, 32, and 33 is output from the terminal 2. Also, this flip-flop 5
Indicator 2 such as a lamp with other outputs of 1, 52, 53
1, 22, and 23 are lit, and it is detected that the selected signal is turned on.

In this circuit example, the switching circuit that actually switches the input signal operates in parallel with the tally display circuit, so even if the switching circuit is disconnected due to a failure, the tally display will still be lit, and the tally display will remain lit. There was a drawback that it could not detect that no signal was being output.

SUMMARY OF THE INVENTION An object of the present invention is to provide a tally detection device which eliminates the drawbacks of the prior art and obtains accurate tallies.

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

FIG. 2 is a diagram showing an embodiment of the present invention. In the figure, input signal number (code signal) generation circuit 1 corresponds to input signals 31, 32, and 33, respectively.
1, 12, and 13 are provided, and the input number display signal (code signal) generated here is sent to the mixing circuit 2.
1, 22, and 23 are superimposed on the input signal.

The input signal number generation circuits 11, 12, and 13 include a code signal generator 1 that generates a number in the form of a code corresponding to an input signal, a carrier signal generator 3 for superimposing this signal on the input signal, and a modulator. It is composed of 2. The configurations of the input signal number generation circuits 12 and 13 are similar to the input signal number generation circuit 11. The input signal on which the code signal is superimposed is input to switching circuits 41, 42, and 43. The output of the switching circuit is divided into two branches, one of which is outputted to the outside from the terminal 5 after the superimposed code signal is removed by the output circuit 51. The other one is the demodulation circuit 52
The code signal is demodulated from the superimposed signal.

The switching circuits 41, 42, 43 are controlled by the output of the decoder 4. The control signal is generated by a controller 1 having a control switch 6 such as a thumbwheel switch or a touch pad, and a control signal generator 7 for converting the signal from the control switch 6 into a code signal.
Given from 0. Furthermore, this controller 10
includes a comparator 8 for comparing the control signal with the signal from the demodulator 52 and a display 9 for displaying the result.

In this embodiment, if the code signal is provided to match the input signal number, the code signal obtained from the demodulator 52 will always match the input signal number. Moreover, this demodulated code signal necessarily passes through the switching circuit, and is obtained only when the main signal is actually output correctly. Then, if the demodulated code signal is compared with the control signal generated in the controller and a match is found, it can be detected that the switching circuit is operating correctly. still. In this embodiment, only three switching circuits are illustrated, but it is clear that other inputs and outputs can also be constructed in the same way.

As described above, according to the present invention, the operation of the switching circuit can be detected correctly in accordance with the actual switching of the main signal.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of a conventional tally detection circuit, and FIG. 2 is a diagram showing an embodiment of the present invention.

Claims (1)

[Claims] 1. A code generation circuit that generates a different first code signal corresponding to each of the plurality of input lines, means for superimposing a signal from the code generation circuit on the corresponding input line, and a means for switching between the plurality of input lines. a switching circuit that selects one line; a demodulation circuit that demodulates the first code signal superimposed on the selected line;
a controller for generating a second code signal for controlling the switching circuit; a comparing means for comparing the second code signal from the controller with the demodulated first code signal; A tally detection device comprising: a display device that displays comparison results.