JPS5532262A - Display circuit for rest time of magnetic tape - Google Patents

Abstract

PURPOSE: To display accurate rest time without reference to the thickness of a magnetic tape by making a decision on the tape thickness by making a comparison between the measured acceleration of a reel desk and the calculated acceleration of a standard-thickness tape and then by deciding on and displaying the tape rest time.

CONSTITUTION: A count value, corresponding to a rotation speed, obtained by rotation speed detector 11 generating pulses and counter circuit 15 is stored in memory circuit 18. Binary adder circuit 20, on the other hand, attains access to a rest calculation formula stored in circuit 18 and then measure the rest time basing upon the rotation speed stored in circuit 18. Similarly, the rest time when the count value of circuit 15 is increased by one is measured through comparator circuit 9 and a difference in rest time corresponding to measured acceleration of the reel desk is compared with the difference arithmetic result at the time of the use of the standard-thickness tape to store a coefficient equivalent to the tape thickness is circuit 18 via circuit 20, etc. Then, circuit 20 calculates the tape rest time corresponding to the thickness basing upon the calculation formula of circuit 18 and rest of tape from the halfway of the tape is accurately displayed on display unit 24 via decoder circuit 23 without reference to the tape thickness.

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