| 摘要 |
PROBLEM TO BE SOLVED: To allow a center side to remotely supervise whether or not status monitor is in normal operation and to simplify testing at the time of installation of a new system or of a system updating. SOLUTION: This status monitor is provided with a data MODEM circuit 2 built in a CATV amplifier 1 to demodulate a polling signal from a center and to modulate a reply signal to a center, and with a controller circuit 3 that controls and diagnoses the amplifier 1 based on the demodulated polling signal and outputs a reply signal in response to the polling signal, and further with a detection circuit 4 that detects the polling signal from the center side to the data MODEM circuit 2 to detect its signal level. The controller circuit 3 has a presence discrimination function that discriminates the presence of the polling signal based on a detection signal of the detection circuit 4, and a fault discrimination function that diagnoses contents of a polling signal demodulated by the data MODEM circuit 2 to discriminate the normally of the polling signal as well as a self-diagnostic function that executes self- diagnosis of a status monitor unit. |
