Two algorithms that are suitable for deriving the blanking level of a National Television Systems Committee (NTSC) composite video signal are described. One method consists of averaging digitized color-burst samples taken from successive scan lines. A second method involves processing a group of samples taken from a single burst interval. Either algorithm used in a hybrid clamping arrangement results in automatic drift compensation and the ability to tie the back porch or sync tip to a predetermined digital output code. This aids in matching the analog signal to the input of the analog-to-signal (A/D) converter for maximum signal-to-noise ratio (SNR). In analyzing the effect of additive noise and timing jitter, it was found that both algorithms are, generally, more vulnerable than a conventional keyed clamper.


Electrical and Computer Engineering

Keywords and Phrases

ADC; NTSC; National Television Systems Committee; SNR; Algorithms; Analog Signal; Automatic Drift Compensation; Blanking Level; Color Television; Composite Video Signal; Digital Codecs; Digital Color Burst Samples; Digital Output Code; Digital Processing; Digital Video Equipment; Hybrid Clamping; Signal-To-Noise Ratio; Video Equipment; Video Signals

International Standard Serial Number (ISSN)


Document Type

Article - Journal

Document Version

Final Version

File Type





© 1992 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

01 Jan 1992