Group coded recording data recovery system

摘要

This relates to a digital data recovery system for decoding group coded data bits stored on magnetic tape whereon a "1" is represented by a flux reversal and an "0" is represented by the absence of a flux reversal with no more than two successive zeros throughout the data record. Input logic detects transitions of input data and forwards this information to an envelope detector which determines if subsequent transitions represent valid data. The presence of valid data enables a data rate detector which determines the average data rate. An output sequencer determines when a decoded output data bit should be generated and its proper polarity.