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Recording Head Access and Settle Time Test

IP.com Disclosure Number: IPCOM000043441D
Original Publication Date: 1984-Sep-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 2 page(s) / 54K

Publishing Venue

IBM

Related People

Herring, GS: AUTHOR [+3]

Abstract

Access and head settle time for a recording head of a flexible disk drive system is tested by monitoring the signal read back from the head after an access operation and by determining if the signal achieves a minimum amplitude after a specified time. To do this, the read-back signal envelope is detected and then compared to a specified reference voltage. The output of the comparator is monitored by a system computer. Further, the read-back signal is monitored for a predetermined period thereafter to ensure that the minimum signal amplitude is sustained. Fig. 1 shows the analog signal read-back from the head in the disk drive. For the drive to read data properly, the peak-to-peak voltage of the read-back signal must be greater than a minimum specified voltage. As shown in Fig. 1, the read-back signal is not adequate. Fig.

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Recording Head Access and Settle Time Test

Access and head settle time for a recording head of a flexible disk drive system is tested by monitoring the signal read back from the head after an access operation and by determining if the signal achieves a minimum amplitude after a specified time. To do this, the read-back signal envelope is detected and then compared to a specified reference voltage. The output of the comparator is monitored by a system computer. Further, the read-back signal is monitored for a predetermined period thereafter to ensure that the minimum signal amplitude is sustained. Fig. 1 shows the analog signal read-back from the head in the disk drive. For the drive to read data properly, the peak-to-peak voltage of the read- back signal must be greater than a minimum specified voltage. As shown in Fig. 1, the read-back signal is not adequate. Fig. 2 shows the configuration of the system used to perform the test. System computer 10 controls the operation of diskette drive 12 and performs the necessary monitoring of the bilevel status signal from analog card 14. Fig. 3 shows the analog card. Difference amplifier 16 receives the bipolar read-back signal from the read head and produces the read- back signal V(A-B) shown in Fig. 1. Peak detector 18 follows the peaks of V(A- B) and produces the envelope signal V(envelope) shown in Fig. 1. Comparator 20 compares the envelope signal to a reference voltage V(ref). Comparator 20 indicates whether the read...