| 摘要 |
PURPOSE:To attain the detection of a fault without interrupting a communication system by comparing 1st and 2nd code conversion signals and outputting a fault signal representing the occurrence of the fault to the ADPCM CODEC when both signals are noncoincident. CONSTITUTION:The 2nd code converting signal is fed to a comparator 43, the 1st code converting signal is fed from a terminal T7 to the comparator 43, where the code converting signals are compared. Since the 1st and 2nd code converting signals are obtained by using the similar data in data RAMs 36 and 46 to apply the code conversion to the same input signal, so long as no fault takes place in both processors 30 and 40, they are coincident with each other. If either of both processors 30 and 40 is faulty, the 1st and 2nd code conversion signals are not coincident, resulting that the comparator 43 outputs a fault signal from a terminal T6. Thus, the fault of the AD(adaptive difference)PCM CODEC 30 is detected while the code conversion is applied by the ADPCM CODEC.
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