LINE QUALITY TEST MECHANISM

摘要

PROBLEM TO BE SOLVED: To conduct a quality test of a line between transmitters without the need of a measurement device whose operation is difficult. SOLUTION: A loop line control section 12 forms a loopback loop for an opposite transmitter at the start of a quality test. When the quality test is started, a PN pattern generating section 13 generates a signal-pattern P, the pattern P is looped back by the loopback loop and a PN pattern synchronization section 15 receives the looped back pattern. The PN pattern synchronization section 15 establishes synchronization of a signal received successively based on the result of receiving the signal pattern P. After the establishment of the synchronization, an error bit insert section 14 inserts an error bit to a signal pattern P to obtain a signal pattern P1 and outputs it to the opposed transmitter. A PN pattern comparison section 16 and a bit number comparison section 17 compare number of the inserted error bits and number E of the error bits in the signal pattern P1 received by the PN pattern synchronization section 15 to conduct the quality test for a line between the transmitters.