Decoder for a communication signal, wherein a status change in the middle of one of said bit cells containing a '1' and at the boundary between two successive in each case, a 'o' takes place bit cells containing

摘要

A decoder is described for a magnetically recorded information signal in which a transition occurs at the center of a bit cell containing a "1," and a transition may occur at the boundary between two successive bit cells containing "0"s. A first synchronous demodulator is receptive to the information signal and a reference wave having a 45 DEG phase. A second synchronous demodulator is receptive to the information signal and a reference wave having a 135 DEG phase. Means responsive to the outputs of the demodulators generate an NRZ output signal having a "1" level when the outputs of the two demodulators have the same polarity, and having a "0" level when the outputs have different polarities.