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Modifying FM Recording Apparatus

IP.com Disclosure Number: IPCOM000092738D
Original Publication Date: 1967-Jan-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Kellogg, JW: AUTHOR [+2]

Abstract

The arrangement is for changing data encoding circuitry to thus record data by a modified FM recording technique. Modified FM recording comprises recording of two clock phases called, respectively, clock bits and data bits. If the data bit is 1, the clock bit is blocked on both sides of the data bit. If the data bit is 0, the clock bit is recorded.

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Modifying FM Recording Apparatus

The arrangement is for changing data encoding circuitry to thus record data by a modified FM recording technique. Modified FM recording comprises recording of two clock phases called, respectively, clock bits and data bits. If the data bit is 1, the clock bit is blocked on both sides of the data bit. If the data bit is 0, the clock bit is recorded.

Prior recording circuitry writes a clock bit every clock time to provide timing. Such circuitry writes a data bit if the data is a 1, blocking the data bit if the data is a 0. The circuitry shown converts this output to modified FM recording by blocking the clock bits both before and after the data bit when the data bit is a 1.

An allow clock signal 10 is utilized by the added circuitry 11 for the above arrangement. Serial data 12 and clock source 13 control latch 14 which is Ored into the allow clock line 10 to block clock 15 if a data bit is present. The latch remains on until the next pulse from clock 13, thus disallowing bits from clock 15 on either side of data bit 12.

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