LINE QUALITY MONITORING DEVICE

摘要

PROBLEM TO BE SOLVED: To reduce the capacity of a conversion table by comparing the number of error pulses counted in unit time with the last one and determining corresponding BER by performing retrieval from a range wherein the number of the pulses increases from the last BER determination position in the increasing order when the number of the pulses increases and from a range wherein the number of the pulses decreases in the decreasing order when the number decreases. SOLUTION: A counter 1 counts the number of error pulses in the unit time set by a time-base oscillator 2 and an address pointer generator 7 sets the last address pointer P' as the pointer P of this time. A 1st comparator 4 compares the current pulse number N with the last error pulse number N' held in a latch 3 to find the increment or decrement. According to the increment or decrement, the address pointer P is increased or decreased by one from an address pointer P' as an origin to obtain as a determined value the address pointer P when the error pulse number N enters the corresponding data range of the pointer P. The data corresponding to the determined value is read out of a 2nd BER conversion table 9.