Consumer Electronics

THE 625-LINE SYSTEM

The CCIR-B standard is adopted by our country. The details of the CCIR-B standard are:

1. Each VHF and UHF television station is assigned a channel that is 7 MHz wide. The composite video signal must fit into the 7 MHz bandwidth.
2. The visual (picture) carrier frequency is 1.25 MHz above the low end of each channel.
3. The aural (sound) carrier frequency is 5.5 MHz above the visual carrier frequency.
4. The chrominance (colour) subcarrier frequency is 4.43361875 MHz above the picture carrier frequency. For practical purposes, the subcarrier frequency is expressed as 4.43 MHz.
5. One complete picture frame consists of 625 scanning lines (585 active lines actually produce the picture. The remaining lines are blanked out during the vertical ...