| 摘要 |
<p>PURPOSE:To make it possible to record a speed control signal and sound signal on the same track by recording a sum signal of the speed control signal and sound signal and their difference signal on a magnetic tape and then by reproducing them for controlling the speed of the magnetic tape. CONSTITUTION:On every arrival of a rectangular pulse signal at input side 11, reference oscillation circuit sends an alternating-current signal of audio frequency range, cycle by cycle, to output side 12. This output is led to plus and minus-side terminals of operational amplifiers 2 and 3 and a sound signal is to the plus-side therminals of amplifiers 2 and 3 via terminal 4. As a result, the sum signal and difference signal of both signals appear at the output sides of amplifiers 2 and 3 and are recorded on magnetic tape 7 through recording heads 8 and 9. Both signals on tape 7 are reproduced by reproducing heads 10 and 11 after time T and led to operational amplifiers 12 and 13. Consequently, amplifier 12 is supplied with the sound signal only and amplifier 13 with the speed control signal only. The speed control signal is inputted to phase comparator circuit 16, where it is phase-compared with the output of oscillation circuit 19, so that a take-up reel will be driven by the output.</p> |
