Recovery procedure for bit value from bi-lingual data stream - using synchronising device to detect bit intervals of three different types, with sequences equated with logical values

摘要

The procedure relates to the recovery procedure of the bit value from a stream of bilingual data. Each bit interval consists of three possible types (a,b,c). An (a)-type bit followed by a (b)-type is associated with a first bit value, and (a) followed by (c) a value equal to that of the preceding bit. A type (c) bit interval followed by the same type of (c) bit interval and an even number of (b)-type intervals is equated with a first logical value, and a similar sequence followed by an uneven number of (b)-type intervals has a second logical value. A demodulator is employed which includes a synchronising unit for two detection members. The data values are used in conjunction with Miller codes for digital magnetic recording.