| 摘要 |
<p>PURPOSE:To exactly discriminate a recording TV signal even in case of a variable speed reproducing mode, by using not only a control signal of a magnetic tape but also rotational frequency of a rotary magnetic head, as a means for discriminating the TV signal. CONSTITUTION:In case of a reproducing mode of a VTR, a control signal recorded in a magnetic tape 1 is reproduced to a control tack pulse head 2, is amplified 3 and is inputted to a switching circuit 4. On the other hand, a disk tack pulse of a rotary magnetic head 5 is detected by a disk tack pulse head 6, is amplified 7 and is inputted to the circuit 4. An output of the circuit 4 is inputted to a frequency detecting circuit 8, and a discriminating signal 9 is obtained. Accordingly, even in case of a variable speed reproducing mode, rotational frequency of the head 5 is inputted in advance as a detecting signal, therefore, in case when a TV signal recorded in the tape 1 has been changed to a TV signal whose field period is different, it can be discriminated easily by the circuit 8. Also, since detection by a pulse reproduced from the tape 1 can be executed, said signal can be discriminated quickly.</p> |
