Burst frame phase synchronizing circuit and burst frame phase synchronizing method utilizing a frame synchronizing signal satisfying a calculated protection condition

A burst frame phase synchronizing circuit for acquiring synchronism for each burst packet by using a synchronous bit set in a head of burst data, comprising:

• means for monitoring a transmission error produced during transmission of said burst data and outputting error information;
• means for outputting protection information obtained by summing up transmission errors based on said error information;
• means for detecting a noncoincidence bit number between said transmitted burst data and a synchronizing pattern for each possible phase and outputting a noncoincidence bit number signal synchronized with each one of said possible phases and indicating each of said noncoincidence bit numbers;
• means for calculating a permissible maximum noncoincidence bit number based on said protection information and outputting a noncoincidence bit number signal detected first among said input noncoincidence bit number signals and satisfying a condition of being less than or equal to said maximum noncoincidence bit number, as a coincidence signal;
• and
• means for correcting phase shifting of said coincidence signal and outputting the corrected signal as a frame synchronizing signal.

A burst frame phase synchronizing circuit for acquiring synchronism for each burst packet by using a synchronous bit set in a head of burst data, comprising:

• a transmission error monitoring circuit for monitoring a transmission error produced during transmission of said burst data and outputting error information;
• a transmission error statistical circuit for outputting protection information obtained by summing up transmission errors based on said error information;
• a frame synchronizing pattern comparator circuit for detecting a noncoincidence bit number between said transmitted burst data and a synchronizing pattern for each possible phase and outputting a noncoincidence bit number signal synchronized with each of said possible phases and indicating each of said noncoincidence bit numbers;
• a plurality of pulse output circuits provided correspondingly to said noncoincidence bit numbers for inputting said noncoincidence bit number signals and outputting pulses synchronized with input phases of said noncoincidence bit number signals;
• a selecting circuit for calculating a permissible maximum noncoincidence bit number based on said protection information, selecting, among pulses output from said plurality of input phase pulse circuits, a pulse output from one of said pulse circuits corresponding to a condition of being less than or equal to said maximum noncoincidence bit number and outputting this pulse as a coincidence signal;
• and
• a frame synchronizing circuit for correcting phase shifting of said coincidence signal and outputting this signal as a frame synchronizing signal.

A burst frame phase synchronizing method for acquiring synchronism for each burst frame by using a synchronous bit set in a head of burst data, comprising:

• a step for monitoring a transmission error produced during transmission of said burst data and calculating error production frequency;
• a step for calculating error frequency for a specified period based on said error production frequency;
• a step for obtaining a permissible maximum noncoincidence bit number from noncoincidence bit numbers in bit strings between said burst data and a specified synchronizing pattern based on said error frequency for said specified period, said maximum noncoincidence bit number being permitted so as to acquire frame synchronism;
• a step for making a comparison for bit strings between said burst data and said synchronizing pattern for each possible phase and detecting a noncoincidence bit number for each possible phase;
• and
• a step for establishing frame synchronization with a timing of a phase corresponding to a noncoincidence bit number which is less than or equal to said maximum noncoincidence bit number and is detected first.