| 摘要 |
PURPOSE:To avoid the effect of S/N deterioration of composite video signal, by separating the composite video signal detected and demodulated from the video recording medium into pattern information signal and composite synchronizing signal, shaping them and synthesizing them. CONSTITUTION:The composite video signal recorded on the video disc 1 is detected at the detector 2, amplified 3 and demodulated at the demodulation circuit 4. This demodulated signal 15 is shaped into the pattern information signal 17 at the shape circuit 5 and separated and shaped into composite synchronizing signal at the synchronous separation circuit 6. Both signals 17, 18 are synthesized at the video signal synthesis circuit 7 to obtain the synthesized composite video signal 21. The signal 15 detected and demodulated from the disc 1 has deteriorated S/N. But, this is separated into signals 17, 18 and synthesis is made after shaping the both signals, no deteoriation is S/N is present is the signal 21, and small sized and low cost laser element can be used as semiconductor laser elements. |
