| 摘要 |
PURPOSE:To make a special adding circuit, etc., unnecessary by detecting the transporting direction of a magnetic tape from the period of a pilot signal or a level in the prescribed timing. CONSTITUTION:A band-pass filter 12 extracts the pilot signal F1 from a reproduction signal, and a rectifier 13 rectifies its output. Figure G1 shows the case where the transporting direction of the magnetic tape at recording is normal, and figure g2 shows the case reverse to said one. Namely in the timing when a sampling pulse (i) is generated, signals g1 and g2 come to high and low levels, respectively. Accordingly the output of a sample and hole circuit 14, which is obtained by sample-holding the output of the rectifier 13 which the aid of the sampling pulse (i) comes to high and low levels when the transporting direction of the magnetic tape at recording is normal and when said direction is reverse, respectively. A deciding circuit 11 monitors the level and decides the transporting direction of the magnetic tape at recording.
|
