In this paper, a few methods for the application of standard time and frequency disseminated by CCTV signal are proposed and some corresponding devices have been developed, such as color subcarrier synthesizer for standard frequency, standard frequency synthesizer using TV line sync signal, sample-and-hold phase detector, TV standard time digital clock, and so on.

This paper presents the basic process of TV signal digitalized,the common technology of compressing code and the essential conception about MPEG video compression standard.

This paper makes more detailed description of the principle and conception of digital treatment of TV signals, including component signal and composite signal, sampling and quantizing, composite coding and component coding.

In allusion to the interruption caused by the unstable program source during the broadcasting of television programs, a kind of switching and controlling system of television signals is introduced.

This paper gives the software design of television signal inspection system,the software system with Visual Basic is developed.

The main research work in this paper includes monitoring the quality and contents of analog TV signals, and the design and implementation of the rea.

Auto-adjust Signal Level of Trunk Line;

The structure and signal level of USB (Universal Serial Bus) and the function of an USB interface chip(PDIUS D12) are presented in this paper.

Mainly analyses several cases of signal level variation in CATV system,and also points out practical methods to be consulted by workers in CATV system.