| 摘要 |
PURPOSE:To detect the receiving level of a slave station by a single level detector and a level deciding means, by securing the selection of a prescribed slave station with use of a switch circuit. CONSTITUTION:The input signal is converted into a proper intermediate frequency converter and applied to a terminal Q through a band pass filter. If it is supposed that the level is detected for a specific station, the burst position signal BPS corresponding the relevant slave station is applied to a switch CH to hold the state. A monostable multivibrator MMV repeats H and L of an output signal synchronously with the signal BPS, and accordingly a sample holding circuit SH holds the signal that is held with the corresponding burst position signal BPS until the next frame. The circuit SH holds a new level detecting signal with the nest signal BPS. When a threshold value detector THL detects that the circuit SH monitors continuously the level of the specific slave station and that the level is lowered, an alarm signal ALM can be produced. |
