| 摘要 |
PURPOSE:To attain the self-diagnosis of the state of a receive while keeping the communication by designating a time slot not in use to apply self-diagnosis. CONSTITUTION:A timing generator 12 receiving a timing signal (a) transmits a time slot gate signal (d) to an AND gate 13 at the position of a designated time slot TS1, Since the gate 13 is being opened by a test control signal (b) at the mode executing the test, the signal (d) is transmitted to a pseudo signal generator 9 via the gate 13, the generator 9 is started and a pseudo signal (g) is inputted to a receiver 6 via a loose coupler 10. When the operation of the receiver 6 is normal, the squelch circuit is operative and a squelch signal (f) is transmitted, but if it is failed, no signal is transmitted. Thus, the signal (f) is fetched to a CPU15 via an FF11, and the propriety of the receiver 6 is discriminated by detecting the signal (f) whether or not it is generated in synchronizing with the slot TS1. |
