公开(公告)号：US4592069A

公开(公告)日：1986-05-27

申请号：US578062

申请日：1984-02-08

申请人： Robert J. Redding

发明人： Robert J. Redding

IPC分类号： H04M19/08 ,  H04M19/00

CPC分类号： H04M19/08

摘要： A modem or other data handling apparatus for connection to a transmission line includes an inductance simulation circuit for providing a low d.c. resistance to allow circulation of a line holding current, whilst presenting a high a.c. shunt impedance to the audio data tones on the line. The simulation circuit comprises two tranistors connected as a high gain amplifier across an input resistor in the modem/line coupling circuit amplifier via a capacitor and the amplifier applies tone signals across the input resistor to augment the tones thereacross. The conductive transistors also act as a low resistance connected across the input resistor for the passage of the line holding current. The simulation circuit acts, in effect, as an inductance, without the use of inductive components. The input resistor is effectively connected, in series with two zener diodes, across the line, and the series circuit receives the line voltage and produces therefrom positive and negative power supplies for energizing the entire modem. No further power supply is necessary.

摘要翻译： 用于连接到传输线的调制解调器或其它数据处理装置包括用于提供低直流电压的电感模拟电路。 阻力允许线路流通，同时具有高的交流电流。 对线路上的音频数据音调分流阻抗。 模拟电路包括两个电阻器，通过电容器连接到调制解调器/线路耦合电路放大器中的输入电阻器上作为高增益放大器，放大器在输入电阻器两端施加音调信号，以增加其上的色调。 导电晶体管还用作连接在输入电阻器两端的低电阻，用于通过线路保持电流。 仿真电路实际上作为电感起作用，而不使用电感元件。 输入电阻器与两个齐纳二极管串联连接，并串联电路接收线路电压，从而产生用于激励整个调制解调器的正极和负极电源。 不需要进一步的电源。