Horizontal synchronization pulse

From Wikipedia, the free encyclopedia

In television, a horizontal synchronization pulse is sent whenever the television set should start scanning a new line.

The format of such a pulse consists of:

1. a 4 µs-long synchronization pulse, where the signal level is set to 0 V
2. a 8 µs calibration delay, where the signal level is set to 0.3 V. The delay is used by the television set to adjust the level of black.

The rest of the scan line follows, with the signal ranging from 0.3 V (black) to 1 V (white), until the next horizontal or vertical synchronization pulse.