JPS6180397A - Automatic voice output checking circuit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] Technical field to which the invention pertains The present invention relates to a downstream warning device used to warn downstream areas when water is discharged from a dam, in which a warning sound is reliably output from a speaker. This invention relates to an automatic audio output confirmation circuit for confirming.

Prior Art Conventionally, in order to confirm that a warning is reliably output from a downstream warning device when water is discharged from a dam, an acoustic signal such as the voice output from a speaker is received by a sound collection microphone and converted into an electrical signal. The operator listens to the output of the sound collection microphone to confirm that the alarm has been output, or checks whether the output level of the sound collection microphone is present or not.

The former has the disadvantage that it cannot save labor because it relies on the human ear, and the latter has the disadvantage that even if a sound other than the alarm sound output from the speaker is input to the sound collection microphone,
There is a risk that the alarm may be mistakenly recognized as being output from the speaker.

OBJECTS OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional drawbacks and to provide an automatic audio output confirmation circuit that can automatically confirm that a warning voice has been output from a speaker.

Structure of the Invention The automatic audio output confirmation circuit of the present invention includes a sound collection microphone that receives sound output from a speaker, converts it into an electrical signal, and outputs it, and subtracts the input signal of the speaker from the output signal of the sound collection microphone. an echo canceller circuit that outputs a signal; and a detection circuit that detects a level difference between the output signal of the echo canceller circuit and the output signal of the sound collection microphone; It is characterized in that when there is no level difference between the output signal of the sound collection microphone and the output signal of the echo canceller circuit, the detection circuit outputs an alarm signal.

Embodiments of the Invention Next, the present invention will be described in detail with reference to the drawings.

The figure is a block diagram showing one embodiment of the present invention. That is, when the alarm audio signal 5 to be issued is input to the speaker 1, the speaker 1 converts the input signal into sound and outputs it to issue an alarm to the downstream area. The sound collection microphone 2 receives the output of the speaker 1, converts it into an electrical signal, and inputs the sound collection signal 6 to the echo canceller circuit 3 and the detection circuit 4. The echo canceller circuit 3 outputs an echo signal 7 obtained by subtracting the input signal of the speaker 1 , that is, the alarm audio signal 5 from the collected sound signal 6 , and supplies the echo signal 7 to the detection circuit 4 .

The detection circuit 4 compares the levels of the echo signal 7 and the collected sound signal 6 during the time period when the alarm audio signal 5 is input, and outputs the alarm signal 8 if there is no level difference, and outputs the alarm signal 8 if there is a level difference. Alarm signal 8 is not output.

When the echo canceller circuit 3 completely cancels the alarm audio signal 5 and the collected sound signal 6, there is no output of the echo signal 7, and the level difference between the collected sound signal 6 and the echo signal 7 is large. Of course, it is possible to confirm that the alarm sound has been output from the speaker 1, but it is clear that even if the canceling operation of the echo canceller circuit 3 is not complete, the echo signal 7 will be at a lower level than the collected sound signal 6. It is. Therefore, by detecting the level difference between the collected sound signal 6 and the echo signal 7 with the detection circuit 4, it can be confirmed that the alarm has been output from the speaker 1. On the other hand, if the sound collection microphone 2 receives other sound even though the speaker l does not output an alarm due to some kind of malfunction, the sound collection signal 6 may be unrelated to the alarm audio signal 5. Since the signal waveform becomes
The level of the echo signal 7 after subtracting is the same as the level of the collected sound signal 6. Therefore, the detection circuit 4 detects that the re-input signals are at the same level and outputs the alarm signal 8.

When the sound collection microphone 2 does not receive any sound, the sound collection signal 6 is of course O, and the echo signal 7 is also O, so the detection circuit 4 detects the same re-input level and outputs the alarm signal 8. do.

Therefore, when the alarm sound is not outputted from the speaker 1, it is possible to know that the alarm signal 8 is not outputted from the speaker 1 by reliably outputting the alarm signal 8. Even if a sound other than the alarm sound is input to the sound collection microphone 2, it will not be mistaken as the alarm sound being output. In this embodiment, since the output of the alarm sound can be automatically confirmed, there is no need for an operator to be assigned, and this has the effect of saving labor. Further, it is possible to completely eliminate the possibility that an external sound is mistakenly recognized as an alarm sound.

Effects of the Invention As described above, in the present invention, an alarm sound output from a speaker is received by a sound collection microphone, and a sound collection signal output from the sound collection microphone and an input signal to the speaker are subtracted from the sound collection signal. Since the output of the speaker is confirmed based on the level difference of the echo signals, it is possible to automatically confirm the output of the alarm sound from the speaker, which has the effect of saving labor. Furthermore, it is possible to completely eliminate the possibility that other sounds input to the sound collection microphone may be mistakenly recognized as the alarm sound output from the speaker.

[Brief explanation of drawings]

The figure is a block diagram showing one embodiment of the present invention. In the figure, 1: varnish beaker, 2: sound collection microphone, 3: echo canceller circuit, 4: detection circuit, 5: alarm audio signal, 6: sound collection signal, 7: echo signal, 8: alarm signal.

Claims (1)

[Claims] a sound collection microphone that receives sound output from a speaker and converts it into an electrical signal; an echo canceller circuit that outputs a signal obtained by subtracting the input signal of the speaker from the output signal of the sound collection microphone; a detection circuit that detects a level difference between the output signal of the echo canceller circuit and the output signal of the sound collection microphone; An audio output automatic confirmation circuit characterized in that when there is no difference in level between the output signals of the echo canceller circuit, the detection circuit outputs an alarm signal.