| 摘要 |
<p>A tape speed determining apparatus for a video signal reproducing apparatus employing a helical scanning system, a rotating head system and a pilot signal system automatically determines a tape speed dependent recording mode of a video tape. The apparatus delays by an infinitesimal time the timing for selection of predetermined ones of a plurality of reference signals supplied at the time of reproduction, as compared with the reproducing head selection timing. An error signal generated during this delayed time is sampled and held for a frame period. A wavelength of a fundamental wave of the sampling output is determined by counting the number of capstan rotation detecting pulses, and thus the recording mode of the video tape is determined as a function of the count value.</p> |
