| 摘要 |
A pulse separator 110 predicts the start of a vertical synchronizing pulse in a video composite synchronizing signal (VCSS) applied via input 105. At a predicted time, the pulse separator 110 provides a start signal via a first output to the bistable 125, thereby causing a signal at output 130 to vary from a first output level to a second output level. When the end of the vertical synchronizing pulse is detected in the VCSS, a stop signal is provided via a second output to the bistable 125, thereby causing the signal at the output 130 to vary from the second level to the first level. A multiplexer (MUX) 615 switched to couple horizontal synchronizing pulses from input 605 to output 620, when a vertical synchronizing pulse is received from input 625, and, switched to coupled pseudo horizontal synchronizing pulses from pseudo pulse generator 610 to the output 620 when a vertical synchronizing pulse is not received from the input 625.
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