| 摘要 |
<p>PURPOSE:To realize an assured detection of the desired signal even though the tape travelling speed control signal is reproduced in an optional tape speed and an optional tape travelling direction, by performing a digital process of the signal and using no band pass filter. CONSTITUTION:A magnetic tape 1 on which the tape travelling speed signal is directly recorded is detected by a magnetic head 2 to obtain a waveform through a reproduction amplifier 3. This signal is applied to a synchronous circuit 5 through a waveform shaper 4. The clock signal is previously applied to the circuit 5 from a clock generator 8, and both the rise and fall timings of the tape travelling speed signal are made synchronous with the clock signal. The signal of the other side is changed to a waveform that shows a rise edge to be differentiated through the 1st differentiating circuit 6 to be applied to an input terminal of either one of AND circuits 16 and 17. This signal is then turned into a waveform delayed by several mus through the 1st delaying circuit 7.</p> |
