The initial small screen control circuit of the small screen VTR

摘要

The circuit is for flickering the initial subscreen for a while after selecting it to identify it to the user in the picture- in-picture (PIP) VTR. A second counter (2) maintains the clear state by a reset signal (S2) while a first counter (1) counts a vertical synchronous signal (S1) of the main screen up to 39. In case of the counter (1) in clear state, the counter (2) counts the clock up to 20. Then on/off control signal (S6) being the same as an output (Q5) of a flip-flop (4) is provided. When the output of a third counter (S3) counting the signal (S6) 4 times is in high level, the subscreen is flickered 4 times for a second by outputs of flip-flops (60,70) of an operation stop controller (5). The flicker is stopped when the counters (10,20) are cleared through an AND gate (G1) by a flip-flop (70).