Apparatus for decoding a serial datastream of channel words into a datastream of information words

摘要

The invention provides for an apparatus for decoding a serial datastream of channel words into a datastream of information words. The apparatus comprises an input terminal (10) for receiving the serial data stream of channel words, a serial-parallel converter unit (16) means for serial-to-parallel conversion of the serial datastream into a parallel datastream of n-bit intermediate channel words. Further, a clock signal generation unit (14) is present for deriving a first clock signal of a specific frequency from the serial datastream of channel words. A frequency division unit (18) is present for dividing the frequency of the clock signal generated by the generation means by a factor of n, so as to obtain a second clock signal of a reduced frequency. A sync word detection unit (24) is available for detecting sync words present in said serial datastream of channel words. Said sync word detection unit (24) is adapted to receive said n-bit intermediate channel words from said serial-parallel conversion unit (16) under the influence of said second clock signal and is further adapted to generate an offset control signal, said offset control signal being indicative of the relative offset, given in numbers of bits, between the start of a sync word and the location of this start position within an n-bit intermediate channel word. A converter unit (26,32) is present for converting said n-bit intermediate channel words into n-bit phase shifted channel words and for converting said phase shifted channel words into information words in response to said second clock signal and said offset signal.