| 摘要 |
PURPOSE:To detect that the tape speed at recording and at reproducing is equal inverting the command signal to generate four kinds of pilot signals for a constant period, and investigating the level change the obtained tracking error signal. CONSTITUTION:Into a pilot signal command circuit 501, a pulse signal is input ted from a microcomputer 106 through terminals 505 and 506. The pulse signal phase-synchronizes an H.SW signal, is a signal having a time width shorter than one field period, and can supply two kinds of reference signals to a balance modulating circuit 1302 of a processing circuit 101 to obtain a tracking signal from a pilot signal generating circuit 301, in one field period at the time of reproduction. The signal having the frequencies fH and 3fH of the difference of the frequency between a reproducing pilot signal and a reference signal is outputted from the circuit 1302, and the output signal of a comparing circuit 1308, and the output signal of a comparing circuit 1308 is given to a level decid ing circuit 104. As the result, even when the error occurs at the signal inputted to the computer 106 more or less, an SP/LP can be automatically discriminated without the malfunction.
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