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Checking the Quality of Magnetic Recording Tape

IP.com Disclosure Number: IPCOM000076288D
Original Publication Date: 1972-Feb-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Related People

Fraim, NR: AUTHOR [+4]

Abstract

This checking system first writes a relatively high-frequency data track and a relatively low-frequency timing track on the magnetic tape being tested, Fig. 1. Writing takes place under closely controlled conditions. Subsequently, the data and timing tracks are read, under the same closely controlled conditions.

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Checking the Quality of Magnetic Recording Tape

This checking system first writes a relatively high-frequency data track and a relatively low-frequency timing track on the magnetic tape being tested, Fig. 1. Writing takes place under closely controlled conditions. Subsequently, the data and timing tracks are read, under the same closely controlled conditions.

During reading, the amplitude of the data track read signal is applied as input to a number of threshold sensitive counters. These counters count and group the read signal into a number of amplitude ranges. The timing track flux transitions divide the tape into discrete record lengths, for example, zones 10 and 11 of Fig. 1. Quality information for each record length, as represented by the state of the count in the threshold sensitive counters, is stored in a digital computer at the end of each record Length.

Fig. 1 shows the tape format which exists after writing. The tape is written on an instrumentation-type recorder having closely controlled tape speed. The tape speed for both the write and the read operation is variable in steps from a low speed of approximately 1 ips to 30 ips. The data track is written at one density for each test. This density is variable in steps from 800 to 60,000 flux changes per inch of tape. Whatever the density, the data track is divided into record lengths, such as zone 10 and zone 11, by the timing track. Each zone includes approximately 16,500 flux transitions of the data track.

Fig. 2 shows the apparatus for reading the tape of Fig. 1 in a manner to accumulate data as to the tape's quality. The rea...