公开(公告)号：US5111502A

公开(公告)日：1992-05-05

申请号：US514131

申请日：1990-04-25

申请人： William C. McClure ,  Bob D. Kunce ,  John Q. McClure

发明人： William C. McClure ,  Bob D. Kunce ,  John Q. McClure

IPC分类号： H04M1/00 ,  H04M1/24 ,  H04M1/27 ,  H04M1/64 ,  H04M1/70 ,  H04M1/82 ,  H04M3/22 ,  H04M11/00

CPC分类号： H04M1/82 ,  H04M3/2272

摘要： A telephone line bridging sensor circuit is provided which provides a variable output frequency signal to a microprocessor for measuring and storing the frequency count on a periodic basis. The circuit includes an isolation transformer to isolate the audio component of the telephone line from the sensing circuit. The loop current present in the telephone line is rectified through a full wave diode rectifier and the output of the rectifier is filtered and regulated to provide an input voltage to an astable, voltage controlled oscillator. As the current on the telephone line varies, the input voltage to the oscillator also varies a proportionate amount causing the output frequency of the oscillator to change accordingly. The output frequency is fed through an optical coupler to a suitable microprocessor circuit for measuring, storing and comparing the frequency readings on a periodic basis to detect differential change in the output frequency indicative of one or more telephone devices bridging the telephone line at the same time.

摘要翻译： 提供了一种电话线路桥接传感器电路，其向微处理器提供可变输出频率信号，用于周期性地测量和存储频率计数。 该电路包括隔离变压器，以将电话线的音频分量与感测电路隔离。 电话线路中存在的回路电流通过全波二极管整流器进行整流，并对整流器的输出进行滤波和调节，以向不稳定的压控振荡器提供输入电压。 随着电话线路上的电流变化，振荡器的输入电压也会随着振荡器的输出频率的相应变化而变化。 输出频率通过光耦合器馈送到合适的微处理器电路，用于周期性地测量，存储和比较频率读数，以检测指示一个或多个电话线路同时桥接电话线路的输出频率的差异变化 。