KR940002193Y1 - Sound intermediate frequency switching circuit for multi tv system - Google Patents

Abstract

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Description

Multi-system voice intermediate frequency automatic switching circuit

1 is a voice intermediate frequency automatic switching circuit diagram of a multi-system according to the present invention.

* Explanation of symbols for main parts of the drawings

100: band pass filter means 200: tuning means

210: oscillator 220: frequency mixing unit

230: 6.0MHZ synchronization unit 300: discrimination means

310: 4.5MHZ synchronization unit 320: discrimination unit

400: switching means 500: detection means

510: 4.5MHZ detector 520: 6.0MHZ detector

600: audio signal trap means BPF1 to BPF4: band pass filter

a: Composite video signal input terminal

The present invention relates to a television and video cassette recorder, and more particularly to each system of the voice intermediate frequencies in a multi-system using all of the sound intermediate frequencies 4.5MHZ, 5.5MHZ, 6.0MHZ, 6.6MHZ. The present invention relates to a voice intermediate frequency automatic switching circuit of a multi-system which automatically switches a frequency corresponding to a frequency.

Function to automatically identify SIF in TV and video cassette recorder of multi-system that use 4.5MHZ, 5.5MHZ, 6.0MHZ, 6.5MHZ, which are generally used as voice intermediate frequency (hereinafter referred to as "SIF") and system switching accordingly Since there was no function and there was no system switching function, there was a problem that the SIF could not be switched automatically according to the function of automatically identifying the SIF even though the SIF could be different for each channel.

The present invention aims to solve this problem, and an object of the present invention is to provide a voice intermediate frequency automatic switching circuit in a multi-system which automatically determines a SIF and switches the system accordingly.

A feature of this invention for achieving this object is a band pass filter means for passing only a corresponding voice intermediate frequency of the input voice intermediate frequencies, and a frequency and a local oscillation frequency from the pass band filter means connected to the band pass filter means. A tuning means for mixing 6.0 MHZ voice intermediate frequency and a band pass filter means for connecting a 4.5 MHZ voice intermediate frequency input and a 5.5 MHZ, 6.0 MHZ, 6.5 MHZ voice intermediate frequency input from the band pass filter means. Discriminating means for discriminating, switching means connected to said discriminating means and tuning means for outputting 4.5MHZ or 6.0MHZ audio intermediate frequency components according to the output state of said discriminating means, and connected to said discriminating means and switching means for said discriminating Detection means for detecting 4.5MHZ or 6.0MHZ according to the output state of the means, the discriminating circuit and the composite Voice intermediate frequency automatic switching circuit of a multi-system comprising voice signal trap means connected to a video signal input and configured to remove voice signal components included in a composite video signal component inputted according to the state of the discrimination circuit. Is in.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a voice intermediate frequency automatic switching circuit of a multi-system according to the present invention, and the frequency from the band pass filter means 100 to the band pass filter means 100 which passes only the corresponding voice intermediate frequency among the inputted SIFs. And the tuning means 200 to mix the local oscillation frequency to obtain 6.0MHZ SIF. The band pass filter means 100 is a 4.5MHZ band pass filter (BPF1) for passing only the SIF of 4.5MHZ input, 5.5MHZ, 6.0MHZ, 6.5MHZ for passing the SIF of 5.5MHZ, 6.5MHZ input respectively And a band pass filter (BPF2) to (BPF4), wherein the tuning means 200 includes an oscillator 210 for outputting a local oscillation frequency of 500 KHZ, the oscillator 210 and the band pass filters BPF2 to BPF4. Frequency mixing unit to obtain a harmonic component of 6.0 MHZ by mixing a 500 KHZ local oscillation frequency from the oscillator 210 and 5.5 MHZ, 6.0 MHZ, 6.5 MHZ SIF from the band pass filters BPF2 to BPF4. And a 6.0MHZ tuning unit 230 connected to the frequency mixing unit 220 to tune the 6.0MHZ harmonic components from the frequency mixing unit 220 to obtain 6.0MHZ SIF.

Then, the band pass filter means 100 is connected with a discrimination means 300 for discriminating the 4.5 MHZ SIF input from the band pass filter means 100 and the SIF inputs of 5.5 MHZ, 6.0 MHZ, 6.5 MHZ. The discriminating means 300 is connected to the 4.5MHZ tuning unit 310 to tune the 4.5MHZ, the band pass filter means 100 and 4.5MHZ to the tuning unit 350 to the vertical pulse (Vertical pulse) period And a discriminating unit 320 for checking the 4.5 MHZ SIF input from the band pass filter means 100. On the other hand, the determining means 300 and the tuning means 200 is connected to the switching means 400 for outputting 4.5MHZ or 6.0MHZ SIF according to the output state of the determination means 300. And the determining means 300 and the switching means 400 is connected to the detection means 500 for detecting 4.5MHZ or 6.0MHZ according to the output state of the determination means 300, the detection means 500 is 4.5 The MHZ detector 510 and the 6.0 MHZ detector 520 are provided. In addition, a voice signal trap means 600 is connected to the determination circuit 300 and the composite video signal input terminal a to trap the voice signal components according to the state of the determination circuit 300 to include the voice included in the composite video signal. The signal is removed to output only pure video signal components.

Since this design is applied to a multi-system, the SIF can be different for each channel, so the band pass filter (BPF1) of 4.5MHZ and the band pass pass (BPF2)-(BPF4) of 5.5MHZ, 6.0MHZ, 6.5MHZ are used. Obtain the SIF of each of the desired 4.5MHZ, 5.5MHZ, 6.0MHZ, 6.5MHZ. That is, when the 4.5MHZ SIF input, 4.5MHZ SIF is inputted to the discriminator 320 through the 4.5MHZ band pass filter BPF1, and the other 5.5 through the band pass filters BPF2 to BPF4. SIFs of MHZ, 6.0MHZ, 6.5MHZ are mixed at 500KHZ local oscillation frequency from oscillator 210 and frequency mixing section 220 to obtain high frequency components of 6.0MHZ, and the harmonic components of 6.0MHZ are 6.0MHZ tuning units (230). ) Is output as SIF of 6.0MHZ. On the other hand, the determination unit 320 outputs a logic "high" only when the 4.5MHZ SIF input using the 4.5MHZ tuning unit 310, and checks the 4.5MHZ SIF input only in the vertical pulse period to prevent the misjudgment by the color carrier. do. The switching means 400 outputs an SIF of 4.5 MHZ when the output of the determination unit 320 is logic "high", and outputs 6.0MZH SIF when the output is "low". The 4.5MHZ SIF and 6.0MHZ SIF signals are input to the detection means 500, and according to the output of the determination unit 320, that is, when the output of the determination unit 320 is logic "high", 4.5MHZ is detected and "low". ", 6.0MHZ is detected and audio signal components of 4.5MHZ, 5.5MHZ, 6.0MHZ and 6.5MHZ are output, respectively. In addition, the voice signal trap means 600 removes the 4.5MHZ component included in the composite video signal at the time of 4.5MHZ SIF input, and 5.5MHZ of each 5.5MHZ included in the composite video signal at the time of 5.5MHZ, 6.0MHZ and 6.5MHZ SIF input. , 6.0MHZ, 6.5MHZ components are trapped to output pure video signals with 4.5MHZ, 5.5MHZ, 6.0MHZ, 6.5MHZ removed respectively.

As described above, the present invention allows each input SIF signal component to be automatically discriminated and switched according to the operation of the discriminating means and the switching means to fit each channel required to meet the needs of the multi-system and is also perpendicular to the SIF discriminating means. The combination of the synchronization frequency and the color carrier frequency components makes it possible to use it as a decision circuit of the current reception system.

Claims (4)

A band pass filter means 100 for passing only a corresponding voice intermediate frequency among the input voice intermediate frequencies and a band pass filter means 100 to mix a frequency from the band pass filter means 100 and a local oscillation frequency. A tuning means 200 to obtain a 6.0 MHZ voice intermediate frequency, and a 4.5 MHZ voice intermediate frequency input from the band pass filter means 100 and 5.5 MHZ, 6.0 MHZ, 6.5 connected to the band pass filter means 100. Determination means 300 for determining the voice intermediate frequency input of the MHZ, and connected to the determination means 300 and the tuning means 200, 4.5MHZ or 6.0MHZ voice intermediate frequency according to the output state of the determination means 300 A detection means 500 connected to the switching means 400 for outputting a component and the determination means 300 and the switching means 300 to detect 4.5 MZH or 6.0 MHZ according to the output state of the determination means 300. And the discrimination meeting A voice signal trap means connected to the video signal input terminal (a) and trapping a voice signal component included in the composite video signal component inputted according to the state of the discriminating circuit 300 to remove the voice signal component; Automatic switching circuit of voice medium frequency of multi-system consisting of 600). 2. The band pass filter means (100) according to claim 1, wherein the band pass filter means (100) passes through each of the voice intermediate frequencies of the input 4.5MHZ, 5.5MHZ, 6.0MHZ, 6.5MHZ. Voice intermediate frequency automatic switching circuit of a multi-system composed. The oscillator 210 of claim 1, wherein the tuning means 200 is connected to an oscillator 210 for outputting a local oscillation frequency of 500 MHz and the oscillator 210 and band pass filters BPF2 to BPF4. Frequency mixing section 220 for mixing only the 500 KHZ local oscillation frequency from the band oscillation frequency and the 5.5 MHZ, 6.0 MHZ, 6.5 MHZ voice intermediate frequencies from the band pass filters (BPF2) to (BPF4) to obtain a harmonic component of 6.0 MHZ, Intermediate speech frequency of the multi-system consisting of a 6.0MHZ tuner 230 which is connected to the frequency mixing unit 220 and tunes the 6.0MHZ harmonic components from the frequency mixing unit 220 to obtain a 6.0MHZ voice intermediate frequency. Automatic switching circuit. The method of claim 1, wherein the discriminating means (300) is connected to the 4.5MHZ tuner (310) for tuning 4.5MHZ, and the band pass filter means (100) and 4.5MHZ tuner (310) for a vertical pulse period. And a discriminating unit (320) for checking the 4.5 MHZ speech intermediate frequency input from the band pass filter means (100).