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Controlling Accurate Inter Block Gaps

IP.com Disclosure Number: IPCOM000091482D
Original Publication Date: 1968-Feb-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Lima, PJ: AUTHOR

Abstract

The width of inter-record or inter-block gaps between groups of data recorded on a magnetic tape is accurately controlled. This is effected by recording a count proportional to the distance or time required for the motor to stop. The stop count is subtracted from a count equivalent to the desired gap width and the remainder count is used to indicate the occurrence of the end of the gap.

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Controlling Accurate Inter Block Gaps

The width of inter-record or inter-block gaps between groups of data recorded on a magnetic tape is accurately controlled. This is effected by recording a count proportional to the distance or time required for the motor to stop. The stop count is subtracted from a count equivalent to the desired gap width and the remainder count is used to indicate the occurrence of the end of the gap.

The motor velocity, as a function of time, is shown at A where full velocity is present prior to time T1 and subsequent to time T4. The Go signal for causing the motor to operate is shown at B. At time T1, a Stop signal is generated and introduced to terminal 10, thus setting latch 12 to condition And 14. Count pulses at 15 either from an oscillator, if the system is to be time-dependent, or from a tachometer associated with the motor, if the system is to be displacement- dependent, are then passed through 14 into previously cleared counter 16. These pulses are recorded in counter 16 until a signal at T2 is introduced to terminal 18, indicating that the motor has reached approximately zero velocity. The signal at 18 resets 12 so as to block any further counts from 16. The actual counts relative to stop time as recorded in 16 are shown at C. The generation of a zero velocity signal at T2 is accomplished by sensing that the back emf of the motor has dropped to zero by a zero velocity detector.

The desired gap length is the total time or displace...