FAULT DIAGNOSTIC DEVICE FOR SINGLE CHANNEL CODING CIRCUIT

摘要

PURPOSE: To obtain a fault diagnostic circuit for a single channel coding circuit in which a fault of the coding circuit is detected even when a channel is busy. CONSTITUTION: A transmitter side analog signal and a test signal outputted from a test signal generating section 7 are added by an adder 4 and the sum signal is converted into a digital signal at an A/D converter 6 and a test signal component is extracted from the digitally converted signal by a BPF 11. Furthermore, the test signal is converted into a digital signal at an A/D converter 9. The test signal component and the digitally converted test signal are compared by a test signal detection section 12, and when they are dissident, it is diagnosed that the A/D converter 6 failed. Moreover, a test signal erasure section 13 erases the test signal from the sum signal between the digitally converted transmitter side analog signal and the test signal.