| 摘要 |
PROBLEM TO BE SOLVED: To provide a field decision circuit for stably discriminating odd and even fields from a composite video signal by a circuit which has simple composition, small scale and no need of extra adjustment. SOLUTION: The field decision circuit comprises a synchronizing separation circuit 1 for separating a composite synchronous signal b from an input composite video signal a, a delay circuit 2 for outputting a shift clock signal c and being connected to the output side of the separation circuit 1, a shift resister circuit 3 holding and bit-shifting the pattern of an equivalent pulse and a vertical synchronous period, by using a clock signal generated at the composite synchronizing signal b, and a decision circuit 4 for obtaining a field discriminating signal e by the decision of the odd and the even fields of the composite video signal according to the decision of the bit pattern provided from the shift resister circuit 3.
|
