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Browse Prior Art Database

Automatic Variable Bandpass Read Chain

IP.com Disclosure Number: IPCOM000078358D
Original Publication Date: 1972-Dec-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Fiorino, BC: AUTHOR

Abstract

Shown is a read chain for a tape drive. Major sections in this read chain consist of variable-frequency clock (VFC) 10, time sense 12, integration detector 14, and phase-error detector 16. The above system configuration is unusual in that all of these major components are automatically frequency-adjusted in response to variations in data frequency, due to changes in tape velocity or density of data.

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Automatic Variable Bandpass Read Chain

Shown is a read chain for a tape drive. Major sections in this read chain consist of variable-frequency clock (VFC) 10, time sense 12, integration detector 14, and phase-error detector 16. The above system configuration is unusual in that all of these major components are automatically frequency-adjusted in response to variations in data frequency, due to changes in tape velocity or density of data.

The automatic frequency adjustment is accomplished by control signals produced from current modulator 18 and current sources 20. Density of the code is indicated by the density-control signal to current modulator 18. Speed of the tape in the tape drive is indicated by the speed-control signal to current sources
20. Analog variations in speed are detected in VFC 10 and provided out of VFC 10 as a voltage level over line 22 to current modulator 18.

Current modulator 18 and current sources 20 monitor the data density and the tape speed information, and, thereafter, provide appropriate currents to drive capacitive storage elements in time sense 12, the delay integrator of VFC 10, integration detector 14, and the voltage-controlled oscillator (VCO) of VFC 10. By changing the drive current to the capacitive storage and thus the rate of charge of the capacitive storage in these units, the frequency responsiveness or bandpass characteristic of these units is adjusted to match incoming data frequencies.

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