Patent ID: 7092435
Filing Date: 2006-08-15
Classification: H04B

Abstract:
1. A line quality monitoring apparatus, comprising: a clock extraction unit configured to extract a clock from a received signal; a first identifier configured to compare the received signal with a first identification level in a phase of the clock extracted by said clock extraction unit, thereby outputting an identification result; a second identifier configured to compare the received signal with a second identification level in the phase of the clock extracted by said clock extraction unit, thereby outputting an identification result; an EX-OR gate configured to calculate an EX-OR of the identification results of said first and second identifiers; an error rate calculation unit configured to calculate a code error rate on the basis of an output from said EX-OR gate and the clock extracted by said clock extraction unit; an amplitude detector configured to detect an amplitude of the received signal; a noise power detector configured to detect noise power contained in the received signal; and a controller configured to control a difference between the first and second identification levels to be inversely proportional to an output from said amplitude detector and to be proportional to an output from said noise power detector.