Browse Prior Art Database

Adjusting Tape Read Signals

IP.com Disclosure Number: IPCOM000091810D
Original Publication Date: 1968-May-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Dattilo, AJ: AUTHOR

Abstract

Tape reading signals are accurately adjusted to maximize the read capability of the equipment. The adjustment minimizes the effect of head skew and eliminates the jitter from variations in speed and bit placement when displaying two signals simultaneously on an oscilloscope.

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Adjusting Tape Read Signals

Tape reading signals are accurately adjusted to maximize the read capability of the equipment. The adjustment minimizes the effect of head skew and eliminates the jitter from variations in speed and bit placement when displaying two signals simultaneously on an oscilloscope.

Tape unit 1, at A, reads tape 2 fed from cartridge 3 past magnetic head 4. Tape 2 is driven by sprocket 5 from motor 6. On the same shaft with sprocket 5 is timing disk 7 having slots spaced in correspondence with character locations on tape 2. The slots are sensed by adjustable lamp and phototransistor assembly 8. The waveforms at B show correct alignment and those at C incorrect alignment of a read gate signal with respect to a detector output signal that is timed to the sensing of a character by head 7. The circuit at D gives alignment indications. Correct alignment is indicated upon a null condition between terminals 9 and 10 by test apparatus 11. The circuit detects relative differences, if any, between a P Pulse which exists from the leading edge of the read gate signal to the leading edge of the detector output, and a Q Pulse which exists from the trailing edge of the detector output to the trailing edge of the read gate signal. These pulses are integrated by integrating networks II 12 and II 13 respectively.

The P and Q voltages at the integrator outputs are a direct indication of the size of one pulse in relation to the other and an indication of the shift...