KR940023245A - Clamp Level Automatic Control Circuit - Google Patents

Abstract

The present invention is to quickly and automatically adjust the clamp level contained in the applied muse signal. A clamp level detecting means and a reference clamp level generating means in a clamp level automatic adjustment circuit of a muse / standard signal converting apparatus for converting an applied muse signal into a digital signal and converting it into a standard NTSC signal. And a difference value generating means, a first switching means, an addition subtraction means, a second switching means, an analog / digital conversion means, and an integration means. Therefore, the input muse signal can be clamped quickly to the level of proper clamp level (128/256) to ensure the accuracy of the clamp level as well as to reduce the time required to extract the appropriate clamp level. There is an advantage that can overcome various deterioration factors caused by the speed.

Description

Clamp Level Automatic Control Circuit

Since this is an open matter, no full text was included.

2 is a block diagram showing a clamp level automatic adjustment circuit according to the present invention, FIG. 3 is a diagram showing a clamp execution time in FIG. 2 is a block diagram, and FIG. 4 is a diagram showing a transmission mode of a mute signal.

Claims (2)

A clamp level automatic control circuit of a mute / standard type signal converting apparatus for converting an applied mute signal into a digital signal and converting the standard type into an NTSC type signal; Clamp level detecting means for detecting a clamp level contained in the muse signal converted into the digital signal; Reference clamp level generating means for generating a reference clamp level for the clamp level detected by said clamp level detecting means; Difference value generating means for comparing the clamp level detected by said clamp level detecting means with a reference clamp level output from said reference clamp level generating means to generate a compound difference having a different sign from each other; First switching means for selectively outputting the plurality of difference values output from the difference value generating means in accordance with the state of the most significant bit of the clamp level detected in the mute signal; Adding and subtracting means for adding and subtracting the clamp level detected in the muse signal to the plurality of differential values selectively output by the first switching means to obtain a correction value of the clamp level; Second switching means for selectively outputting the added value and the subtracted value output from the adding and subtracting means according to the state of the most significant bit of the clamp level detected in the mute signal; Analog / digital converting means for converting the signal selectively output from the second switching means into an analog signal; And integrating means for integrating the signal output from the analog / digital converting means during the horizontal synchronous signal period of the horizontal clamp signal and inserting the signal into the muse signal. 2. The apparatus of claim 1, wherein the difference value generating means comprises: first subtracting means for generating a first difference value between a clamp level detected by the clamp level detecting means and a reference clamp level output from the reference clamp level generating means; And a second subtracting means for generating a second difference value different from the first difference value and a sign by inputting the detected clamp level and the reference clamp level applied to the first subtraction means. Level automatic control circuit. ※ Note: The disclosure is based on the initial application.