| 摘要 |
PURPOSE:To improve the reliability of a fault detection system by using an input signal as an output of a built-in matrix circuit of a television audio multiplex modulator. CONSTITUTION:In case of the stereo broadcast, an L signal and an R signal of program signals being audio input signals are fed to a matrix circuit 41 via a preemphasis circuit respectively. An (L+R) signal and an (L-R) signal are extracted at the output side of the matrix circuit 41 by applying the impedance matching by taking the avoidance of the operation characteristic of an audio multiplex modulator 4 into account and they are applied as inputs to detectors 1, 2. The detectors 1, 2 use the (L+R), (L-R) signals for input/output comparison so as to attain stable and accurate comparison of the both even when the same program signal is given in the L, R signals thereby improving the reliability of fault detection remarkably. |
