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Browse Prior Art Database

Hybrid Data Separator Adapter

IP.com Disclosure Number: IPCOM000044296D
Original Publication Date: 1984-Dec-01
Included in the Prior Art Database: 2005-Feb-05
Document File: 2 page(s) / 51K

Publishing Venue

IBM

Related People

Smith, BA: AUTHOR

Abstract

A technique is described whereby an inexpensive hybrid data separator adapter is used to increase the effectiveness of diskette recording media by providing frequency modulation (FM) technology on track zero in the event design standards require it. Since many diskette recording adapters support only modified frequency modulation (MFM), the proposed adapter circuitry is added to existing circuitry, as shown in the dotted area of the drawing. A digital data separator (DDS) 10 is added to handle the FM decode and requires only a reference clock 11 and the incoming diskette data 12 to decode data for the diskette controller 13. The DDS 10 circuit is limited to operating on track zero only. A typical device to provide this function would be a 9216 integrated circuit which is considered appropriate for the 125 Kbps FM signals.

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Hybrid Data Separator Adapter

A technique is described whereby an inexpensive hybrid data separator adapter is used to increase the effectiveness of diskette recording media by providing frequency modulation (FM) technology on track zero in the event design standards require it. Since many diskette recording adapters support only modified frequency modulation (MFM), the proposed adapter circuitry is added to existing circuitry, as shown in the dotted area of the drawing. A digital data separator (DDS) 10 is added to handle the FM decode and requires only a reference clock 11 and the incoming diskette data 12 to decode data for the diskette controller 13. The DDS 10 circuit is limited to operating on track zero only. A typical device to provide this function would be a 9216 integrated circuit which is considered appropriate for the 125 Kbps FM signals. Since the FM mode is only operational at track zero, any problems typically encountered with digital data separators are minimized due to the lack of a bit shift on the outer tracks of a diskette. The combination of an analog MFM data separator 14 and the DDS 10 FM circuit provides a higher functional compliance with data interchange standards without compromising performance in critical MFM circuitry.

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