| 摘要 |
<p>PURPOSE:To eliminate defectives of a magnetic tape feed mechanism by counting pulses generated by reel tachometers and by detecting information on slide generation when a difference in count value exceeds a fixed value. CONSTITUTION:Beams passing through many slits provided in the circumferential surfaces of reel tachometers 13 and 14 are detected by photoelectric sensors 20a and 20b, and 21a and 21b arranged at intervals of a fixed angle. Therefore, pulses from sensors 20a and 21a are sent to up-down counters 24 and 25 through amplifiers 22a and 23a and then counted by them to their rotational amounts. Further, output pulses of amplifiers 22a and 23a and those of sensors 20b and 21b are sent to driving-direction deciding circuits 26 and 27 by way of amplifiers 22b and 23b to decide turning directions of reels. Count values of counters 24 and 25 are sent to difference detecting circuit 28 for subtraction and comparing circuit 29, when the output of circuit 28 is greater than a referecne value, generates a slip generation signal. Since the simple circuit like this detects a slip of a reel tachometer easily, problems of the tape feed mechanism can immediately be solved.</p> |
