KR930009182B1 - Signal separating system - Google Patents

Abstract

The system for separating composite synchronous signal and digital data from composite video signal in an optical video disc system, comprises: a clamping circuit for clamping input composite video signal means for separating composite synchronous signal from the clamped composite signal, means for separating vertical synchronous signal from the composite synchronous signal, and means for generating gate pulse and separating digital data from the composite synchronous signal and the vertical data from the composite synchronous signal and the vertical synchronous signal. Thus this invention can provide static vertical and horizontal synchronous signal and digital data regardless of frequency of video signal.

Description

Synthesis Synchronization Signal and Digital Data Separation System from Composite Image Signal

1 is an NTSC composite video signal.

Figure 2a is a block diagram of a composite synchronization signal and digital data separation system from the composite video signal of the present invention.

2b is a block diagram of a synthesized synchronous signal (horizontal synchronous signal) separator.

2c is a block diagram of a vertical synchronous signal separator.

2d or block diagram of a digital data separator.

3 is a waveform diagram of each part according to an exemplary embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

1: Clamp Circuit 2: Synchronous Synchronous Signal Separator

3: first comparator 4: low pass filter

5: vertical synchronous signal separator 6: gate pulse generator

7: digital data separator 8: first low pass filter

9: Buffer Circuit 10: Level Shift Circuit

11: peak-to-peak detection circuit 12 second low pass filter

13: second comparator 14: third comparator

15: reference voltage (Vref)

The present invention relates to a video signal system, and more particularly, to a composite synchronous signal and a digital data separation system for separating horizontal and vertical synchronous signals and digital data from a composite video signal read from an optical video disc system.

Generally, NTSC (National Television System Committee) composite video signal has vertical sync signal and digital data included in horizontal blanking signal and vertical blanking period for synchronization of basic clock. Especially in optical video disc system The digital data gives the user special information to be used to control the special function and to give picture form and time information.

Accordingly, an object of the present invention is to implement a system that accurately separates synthesized synchronous signals and digital data from NTSC composite video signals.

Synthetic synchronous signal and digital data separation system of the present invention for performing the above object, the clamping unit and the clamped synthesis to clamp the level of the synthetic synchronous signal and digital signal before the input composite video signal into the synthetic synchronous pulse separation circuit It consists of a composite synchronous signal separator that separates the composite synchronous signal and digital data from the video signal, a vertical synchronous signal separator that extracts only vertical synchronous pulses through a low pass filter, and a digital data separator that separates the digital data. Hereinafter, described in detail with reference to the accompanying drawings.

In the present invention, the input composite video signal configured as shown in FIG. 1 is divided into a horizontal synchronization signal, a vertical synchronization signal, and digital data.

2A is a clamp circuit part 1 for clamping a synchronization signal and a digital signal level of an input composite video signal as shown in the entire block diagram of the present invention for separating the composite synchronization signal, the vertical synchronization signal, and the digital data from the composite video signal. The synthesized synchronous signal separator (2), which separates the synthesized synchronous signal and the digital data from the clamped composite video signal, compares the output of the buffer circuit and the peak detection circuit in the synthetic synchronous signal separator (2) and synthesizes the output. A first comparator (3) for synchronizing signals (a horizontal synchronizing signal and a vertical synchronizing signal), a low pass filter (4) for removing high frequency components, and a low pass filter for extracting only vertical synchronizing pulses from the synthesized synchronizing signal separator output. A vertical synchronous signal separator (5), a gate pulse generator (6) generating a gate pulse by inputting the vertical synchronous signal output and a composite synchronous signal output, and A digital data separator (7) for separating digital data using the gate pulse of the gate pulse generator (6) as an adjustment terminal from the conventional synchronous signal separator (2) is connected. 2b, c, and d are shown.

FIG. 2B shows the composite synchronous signal separator 2 for outputting the composite synchronous signal in detail. The clamped composite video signal passes through the first low pass filter 8 through which the data signal is passed and the high frequency component of the color signal is removed. The passed data signal is level-shifted in the level shift circuit 10 via the buffer circuit 9 and passed through the peak-detection circuit 11 for detecting the peak value, and output from the buffer circuit 9. The synthesized synchronous signal is output through the first comparator 3 comparing the output of the peak detection circuit 11 with the synthesized synchronous signal.

FIG. 2C shows a vertical synchronous signal separator 5 for extracting a vertical synchronous signal from a composite synchronous signal including a horizontal synchronous signal and a resin synchronous signal, and shows a low frequency in the synthesized synchronous signal output from the synthesized synchronous signal separator 2. Through a second comparator 13 which compares the output obtained through the second low pass filter part 12 which removes the horizontal synchronization signal and the digital data by passing only the component 12 and the reference voltage 15 (Vref) caught therein. The vertical synchronization signal is output.

FIG. 2D shows a detailed view of a gate pulse generator 6 for generating a gate pulse from a synthesized synchronous signal and a digital data separator 7 for separating digital data using the generated pulse as an adjustment terminal. The composite synchronous signal output from the signal separator 2 and the vertical synchronous signal output from the vertical synchronous signal separator 5 are input to output the gate pulse only for the period of digital data, and the third comparator 14 The output from the synthesized synchronous signal separator 2 is input, and digital data is output by adjusting the gate pulse output from the gate pulse generator 6.

Referring to the waveform diagram of FIG. 3 and applying the waveform diagram of the present invention to FIG. 2A of the present invention, the input will be a composite synchronous signal (horizontal synchronous signal and vertical synchronous signal), an equalization pulse signal, as shown in FIG. It is NTSC composite video signal composed of digital data. After the input composite video signal is clamped and passed through the first low pass filter 8, the video signal is inverted as shown in the waveform of (b) to enter one input terminal of the first comparator 3, and the DC level is shifted to peak. The DC voltage level waveform C, which has passed through the value detecting circuit, is input to the other input terminal of the first comparator. The synthesized synchronous signal waveform d obtained above is input to the second comparator 13 through the second low pass filter 12 to output the vertical synchronous signal waveform e. The synthesized synchronous signal waveform d and the vertical synchronous signal waveform e are input to the gate pulse generator 6 to obtain an output waveform f for generating a gate pulse only when a digital data signal is present among the synthesized synchronous signals. The synthesized synchronous signal waveform d input to the indentation third comparator 14 obtains the digital data waveform g by the gate pulse waveform f.

The present invention is a simple structure separation system, which extracts only the vertical synchronization signal from the composite synchronous signal obtained from the composite video signal and separates the digital data using the gate pulses from the composite synchronous signal and the vertical synchronous signal obtained from the composite video signal. Regardless of frequency, stable horizontal and vertical synchronization signals and digital data can be obtained.

Claims (4)

A clamp circuit (1) for clamping the input composite video signal, a composite synchronous signal separator (2) for dividing the composite synchronous signal from the composite video signal clamped by the clamp circuit, and a composite synchronous signal including horizontal and vertical synchronous signals. Synthesized from a composite video signal characterized in that it comprises a vertical synchronous signal separator (5) for separating the vertical synchronous signal, and a digital data separator (7) for separating the digital data by generating a gate pulse from the synthesized synchronous signal and the vertical synchronous signal. Synchronization signal and digital data separation system. 2. The synthesized synchronous signal separator (2) according to claim 1, comprising: a low pass filter (8) for passing data signals and removing color image signals, a buffer circuit (9) for outputting a low pass composite video signal as an output, a buffer circuit A level shift circuit (10) for level shifting the output of the peak, a peak value detection circuit (11) for level shifting to detect the peak value, and a second value for comparing the peak value detection value of the output of the buffer circuit and the peak value detection circuit A synthesized synchronous signal and digital data separation system from a composite video signal, characterized in that it comprises a comparator (3). The second low pass filter 12 and the second low pass filter 12 of claim 1, wherein the vertical synchronous signal separator 5 separates the vertical synchronous signal by passing only low frequency components from the synthesized synchronous signal output from the synthesized synchronous signal separator 2. And a second comparator (13) for separating the vertical synchronous signal by comparing the output of the low pass filter with a reference voltage (15: Vref). 2. The gate pulse of claim 1, wherein the digital data separator (7) generates a gate pulse only during a period in which there is digital data from a synthetic synchronous signal from the synthetic synchronous signal separator and a vertical synchronous signal from the vertical synchronous signal separator. And a third comparator 14 for inputting the synthesized synchronous signal output from the synthesized synchronous signal separator and outputting digital data from the gate pulse output from the gate pulse generator 6. Synthesis synchronous signal and digital data separation system from composite video signal.