| 摘要 |
PURPOSE:To realize the matching of tracking, by tracing the recording track by giving a displacement to a video head with an inclination according to the tape travelling speed and giving an up- or down-displacement to the video head when a shift is caused to the tracking with a reduction of the reproduced signal level. CONSTITUTION:The output frequency (f) of a frequency generator attached to the shaft of a capstan motor is converted into the DC voltage through an fV converter 12 to produce the sawtooth wave through a waveform generating circuit 12. On the other hand, a reproduction signal (e) obtained from a video head is compared with the prescribed voltage which is supplied in accordance with a switch signal SW that produces an envelope through a reproduced envelope detecting circuit 14 and is supplied to comparators 16 and 16' to give a switching action to the video head with 30Hz. When the reproduced level signal is lower than the prescribed voltage, the outputs (b) and (b') are produced from differ- entiating circuits 17 and 17' to invert T flip-flops 18 and 18'. Then track pitch displacement outputs V1 and V1' are added to the waveform generation output V0 when the Q outputs of the flip-flops 18 and 18'. thus a head displacement output is produced to the bimorph from high voltage amplifiers 13 and 13'. |
