| 摘要 |
PURPOSE:To conduct various tests without need of special design and adjustment by generating a reference carrier at other reference reception circuit using a local oscillation signal of a reception circuit to be tested while giving no distortion to a transmission data. CONSTITUTION:A transmission signal outputted from a transmission circuit 1 and modulated is fed to other reference reception circuit 6 than a reception circuit 4 to be tested while the level is adjusted by an attenuator 5 and a carrier is obtained by a carrier recovery function of the reception circuit 6. A signal fed to the reception circuit 4 to be tested is subject to addition of noise by a pseudo transmission line 3 and its carrier power versus noise power (C/N) is much reduced, and the recovered carrier from the reception circuit 4 to be tested cannot be used as a stable recording signal, but since the transmission signal branched from a distributer 2 has less noise or distortion, since the signal is used for the recovery of a stable carrier, jitter of the carrier recovered by the reception circuit 6 is very less and usable for the reference carrier and the wave is used for a test for cycle skip or the like. |
