FRAME ALIGNMENT CIRCUIT AND ENCODING/DECODING PROCESSING CIRCUIT USING THE CIRCUIT

摘要

PURPOSE: To shorten alignment recovery time and to evade erroneous alignment by detecting an auxiliary bit from input encoded data, utilizing the detected output and detecting a frame bit from the input encoded data. CONSTITUTION: An encoding processing part 2 inserts the auxiliary bit and the frame bit to data scrambled in a scramble part 1 and performs encoding. A comparison part 41 compares (i)-th and (i+1)-th encoded data inputted from a digital transmission line and detects the auxiliary bit. A frame alignment detection part 43 generates the output timing of frame information and the frame bit, generates the information for setting and resetting a descramble part 5 and generates frame protective information. An alignment protective part 44 protects frame alignment and outputs the alarm of the frame alignment. The descramble part 5 returns the scrambled data to original digital signals and a decoding processing part 6 eliminates the auxiliary bit and the frame bit of the encoded data.