| 摘要 |
A d.c.-coupled video clamping circuit is disclosed for operation with normal video signals and sync suppressed scrambled video signals. For receiving normal video signals, a feedback path detects variations in sync tip level from a reference level and applies a corresponding control voltage to a d.c. signal amplifier, thereby to clamp and maintain the sync tip at a fixed (black) level. For receiving sync suppressed scrambled video signals, the feedback path is disabled and a fixed reference voltage is applied to the d.c. signal amplifier. |
