JPS63203080A - monitoring device - 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 Field of Industrial Application The present invention relates to an audio/video monitoring device.0 Prior Art Conventionally, this type of device has K) As shown in Fig. 3, the sound transmitter I
K TV camera 10, gate circuit 12.19, transmitter 1
4, synchronous signal generation circuit 11, S/H circuit 15, adder 1
3. Audio signal sample page 2.

field circuit 15, A/D converter 16, digital processing circuit 1
7 and a check code addition circuit 18, and the receiving section 2 includes a receiver 21, a gate circuit 22, an adder 23,
It includes a synchronization signal generation circuit 21, a data separation circuit 25, a digital processing circuit 26, a D/A converter 28, an error correction circuit 27, and a character generation circuit 24. According to Kone, in the transmitter I, the audio signal is sampled and held in the S/H circuit 15, then digitized in the A/D converter 16, and then in the digital processing circuit 17, the audio signal is sampled and held in the S/H circuit 15. A check code addition circuit 18 inserts a check code into the time band and also adds a check code for error correction.
The audio signal is added by the adder 13 via the gate circuit 19 and then transmitted, and the audio signal is digitized according to the set time band in the receiving section 2 and separated by the data separation circuit 25. The character generating circuit 24 and the adder 23 insert and display a graphic pattern image in the added portion.

Problems to be Solved by the Invention However, in the above-mentioned conventional apparatus, in order to insert the audio signal into the set time band during the 1 fee 3 basis, check codes for error correction are added, or the audio signal is separated. When this happens, a part of the video signal is deleted, and a character generation circuit 24 must be provided for this purpose. The present invention solves these conventional problems, and by inserting an audio signal into the H blanking period, it does not affect the video signal at all and does not require a check code addition circuit or a character generation circuit. The object of the present invention is to provide an excellent device that can realize superimposition and separation of a video signal and an audio signal with a small amount of circuitry.

Means for Solving the Problems In order to achieve the above object, the present invention includes an audio circuit, a circuit for sampling the audio signal, a circuit for superimposing the sampled audio signal during the horizontal blanking period of the video signal, and A circuit for converting a constant current into a constant voltage is provided, and the monitor section is also provided with a circuit for sampling and holding an audio signal from a video/audio signal, an audio output circuit, and a circuit for converting a constant voltage into a constant current.

Therefore, according to the present invention, an audio signal can be superimposed on a video signal with a small amount of circuitry, and a DC power supply can also be superimposed to transmit the video signal and the audio signal with a single coaxial cable. .

Embodiment FIGS. 1 and 2 show an embodiment of the present invention, in which FIG. 1 is a block diagram of a camera section, and FIG. 2 is a block diagram of a monitor section. In FIG. 1, 31 is an image sensor, 32 is a video amplification circuit, 33 is a synchronization signal generation circuit, and 35
is an ECM, 36 is an audio amplification circuit, 37 is a sampling circuit, 34 is a sampling pulse generation circuit, 38 is a circuit for clamping a video signal, 39 is an impedance conversion circuit, 40 is a constant voltage circuit, and 42 in FIG. 2 is a constant current. 41 is an impedance conversion circuit, 43 is a clamp circuit, 44 is a video amplification circuit, 46 is a synchronous separation circuit, 48 is a sample hold circuit, 47 is an S/H pulse generation circuit, 4
5 is a CRT, 49 is an audio 5 page amplification circuit, and 50 is a speaker.

Next, the operation of the above embodiment will be explained. In the camera section of the above embodiment, the synchronization signal generating circuit 33 generates a sampling pulse of a phase located on the back porch during the horizontal (H) blanking period using the horizontal synchronization signal.
Hanging table made with 4. Therefore, the frequency of this pulse is 15.
734 KHz, which means that signals up to about 8 KHz can be sampled, and this sampling frequency is sufficient for the audio band, especially for monitoring purposes. The output of the audio amplification circuit 36 is sampled using this sampling pulse. Since the sampled audio signal is located on the back porch of the H blanking period, it can be directly superimposed on the clamped video signal. In the monitor section, the video/audio signals are transmitted superimposed on the constant current, so the APL fluctuations are large and the clamp circuit 43
Clamp some parts with.

Since the audio signal is superimposed on the H blanking period and does not affect the video signal, the video signal is directly amplified by the video amplification circuit 44 and displayed on the CRT 456. On the other hand, regarding the separation of the audio signal, the sampling and hold pulse generation circuit 47 generates a pulse for S/H of the audio signal using the horizontal synchronization signal synchronously separated by the synchronization separation circuit 46.

After S/H is performed by the sampling hold circuit 48, the signal is amplified by the audio amplification circuit 49 and output to the speaker 5o.

In this way, according to the above embodiment, only 34, 37 and 38 in FIG. 1 are used for superimposing video and audio signals, and 47, 48 and 38 in FIG. 2 are used for separating and outputting video and audio. As it is composed of only 49.50,
This has the effect of allowing video and audio to be transmitted using a single coaxial cable with a small amount of circuitry.

Effects of the Invention As is clear from the above embodiment, the present invention can superimpose and separate a video signal and an audio signal with 5 times less circuitry, and by superimposing a DC power supply, only one coaxial cable is needed between the camera section and the monitor section. I can't get enough of books.

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[Brief explanation of the drawing]

FIG. 1 is a block diagram of a camera section of a monitoring device according to an embodiment of the present invention, FIG. 2 is a block diagram of a monitor section, and FIG. 3 is a block diagram of a conventional monitoring device. 31... Imaging confectionery, 32... Video amplification circuit, 34...
...Sampling pulse generation circuit, 35...ECM,
36... Audio amplification circuit, 37... Sampling circuit, 38... Clamp circuit, 39... Impedance conversion circuit, 40... Constant voltage circuit, 41... Impedance conversion circuit, 42... Constant current circuit, 43... Clamp circuit, 44... Video amplification circuit, 45... CR
T, 46... Synchronization separation circuit, 47... S/H pulse generation circuit, 48... S/H circuit, 49... Audio amplification circuit, 50... Speaker.

Claims (1)

[Claims] An audio signal sampled during the horizontal blanking period of the video signal is superimposed and transmitted, and the transmitted signal is sampled and held using a sample-hold pulse created by a horizontal synchronization signal separated from the transmitted signal to obtain audio output. A monitoring device designed to