| 摘要 |
PURPOSE:To attain stable Y/C timing correction, by adding SYNCs of opposite plarity to an I and a Q at recording and separating the SYNCs with the subtraction of I-Q at reproduction so as to detect normally and stably the time shift of Y and C signals. CONSTITUTION:Y, I, Q are synthesized at a matrix 1 with R, G, B, the SYNC is added to the I and Q in opposite polarity at synchronizing signal addition circuits 2, 4 and recorded at heads 14, 15 with FM modulation at FM modulators 6-8. The Y signal is demodulated at an FM demodulator 18 at reproduction and outputted via a fixed delay line 21. The I, Q signals demodulated at FM demodulators 19, 20 are outputted via variable delay lines 22 23, they are subtracted with each other at a substractor 25, the SYNC is separated at a synchronizing signal separator circuit 26, the SYNC of the I only passes through a gate 27 and the synchronizing separation is attained at the 50% level of the SYNC of the I at a synchronizing signal separator circuit 28. The shift between the Y and I is detected at a phase detector 29, the delay amounts of the delay lines 22, 23 is controlled and the time axes of the Y, I, Q are made coincident. |
