| 摘要 |
<p>PURPOSE:To always decide the recording tape speed with high stability with no use of a control signal by deciding the recording speed from the information on the reproduced pilot signal. CONSTITUTION:The fS component of a pilot signal is always detected with LP heads A and B of narrow width regardless of the state of a head which is reproducing a video signal. Based on this detecting information, the speed of the recording tape is discriminated. In other words, both outputs CFG and P of a frequency generator 7 and a zero-cross detector 17 are supplied to a discriminating circuit 18. An SP is decided if the ratio R between the frequency fCFG of the generator 7 and the frequency fP of the detector 17 is larger than 12. While an LP is decided when the ratio R is smaller than 12. Then the reproduction mode is automatically switched for a switch 19 and a servo circuit 5. Thus, the discrimination of recording tape speed with high stability with no use of a control signal is always made possible.</p> |
