| 摘要 |
PURPOSE:To ensure the high-reliability code detection by applying the input signal to one side of the input terminal of each phase detector along with the reference carrier with the phase shift given by the fixed angle applied to the other side of the input terminal each and then giving the identification to the output. CONSTITUTION:In case he code error detection is carried out for monitor of the circuit quality of the digital communication transmission line, the input signal is branched off into four parts to be applied to one input end of phase detectors 1-4 each along with the reference carrier applied to the other side of each input end. The reference carrier is then applied to detectors 1-4 with the phase shift of pi/2, 0. +DELTAtheta and -DELTAtheta each given, and each output is supplied to discrimination circuits 8-11. Then the outputs of circuits 8 and 9 are used as channels CH1 and CH2 each, and the outputs of circuits 10 and 11 are connected to the two input of exclusive logical sum circuit 12 in order to obtain the code error signal at the output of the circuit. As a result, the value of DELTAtheta which causes the deterioration can be reduced down to about 1/2, thus ensuring the high-reliability detection for the code error. |
