JPS5140111

• Main Author: NOBORU KIMURA
• Format: Patent
• Language: English
• Published: 03.04.1976
• Subjects: BASIC ELECTRONIC CIRCUITRY; CODE CONVERSION IN GENERAL; CODING; DECODING; ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; INFORMATION STORAGE; INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORDCARRIER AND TRANSDUCER; PHYSICS; TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHICCOMMUNICATION

Apparatus and method for high track density magnetic recording and retrieval. A decoder-coupled five bit shaft register converts an incoming data bit stream to a converted data bit stream having successive groups of five bits corresponding to successive groups of four bits of the incoming stream, the converted stream having not more than two adjacent binary "1's". A shift register-coupled NRZO encoder provides a self-clocking tri-frequency signal allowing a clocking window margin of one-half a converted bit cell. The tri-frequency signal has a primary frequency component and additional frequency components of one-half and one-third the primary frequency and is applied to an NRZO encoder coupled modulator. The modulator introduces flux reversals at double the primary frequency following the maintenance of the three-frequency signal in excess of one bit cell interval, enhancing the ratio of timing margin to maximum distance between flux reversals. Both fringing field effects on adjacent tracks and intersymbol interference between linearly adjacent bits of a magnetic recording medium are minimized in a storage system having a track density in excess of about 500 tracks per inch and a linear bit density on the order of 4000 bits per inch. An amplifier-coupled slope detector detects playback signal slope polarity changes to provide a coded output signal.