PULSE TOGGLE MONITOR CIRCUIT

摘要

TITLE PULSE TOGGLE MONITOR CIRCUIT A pulse toggle monitor circuit which detects the duration of toggling of a monitored pulse. A plurality of detection circuits are connected in a shift register manner. This arrangement provides for detection of pulse dialing of a duration longer than a predetermined time as defined by the period of an external reference signal and the number of detection circuits. The output of the shift register is connected to a storage circuit which is clocked by the reference signal and operates to store failure signals from the shift register. The storage circuit can be cleared either by external control or detection of a valid pulse.