| 摘要 |
<p>PURPOSE:To provide an automatic discriminating circuit which can discriminate a recording time mode in any reproducing state, by detecting whether a prescribed-numbered FG pulse exists in one control pitch or not with respect to discrimination of a recording time mode at the time when interrupted running such as frame feeding or the like is performed in a magnetic recording and reproducing device. CONSTITUTION:A control pulse reproduced by a control head 1 is amplified by an amplifier 2, and the FG pulse from an FG6 of a capstan motor 5 is amplified by an amplifier 7, and these control pulse and FG pulse are inputted to an automatic discriminating circuit 3 to discriminate a recording time, and rotation of the capstan motor 5 is controlled by a driving control circuit 4. If the number of FG pulses of the capstan motor rotated in one control pitch is N+ or -alpha (alpha is about 5% of N) in the standard mode, said number if N/3+ or -beta (beta is about 5% of N/3) in the triple mode; and therefore, it is detected whether, for example, the (2/ 3N)th FG pulse exists in one control pitch or not to discriminate a recording time mode between the standard mode and the triple mode.</p> |
