| 摘要 |
<p>PURPOSE:To simplify the setting of a recording medium speed adequate for the frequency band of a signal by detecting a difference, between the power value of the original signal of a recording signal supply circuit and that of the reproduced signal of a reproduced signal output circuit, being less than a fixed value. CONSTITUTION:As a recording signal supply circuit, amplifier 2 and FM modulator 3 are provided connecting to recording head 4. Magnetic tape 5 in contact with head 4 runs as shown by arrow 10 through the working of reels 6 and 7, capstan 8, and pinch roller 9. To the output of reproducing head 11, a reproduced-signal output circuit is provided which consists of reproducing amplifier 12, FM demodulator 13, change-over switches 14-17, LPFs 18-21, and output terminal 22. In this case, the power value of the original signal outputted by amplifier 2 and that of a reproduced signal are led into differential amplifier 29, whose difference output is averaged 30 and compared 31 with reference voltage 32 to obtain a fixed output, thereby exercising control 25 over a tape speed. Consequently, a recording medium speed suitable to the frequency band of a signal can easily be set.</p> |
