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公开(公告)号：US4113996A
公开(公告)日：1978-09-12
申请号：US798787
申请日：1977-05-20
IPC分类号： H04B1/58
CPC分类号： H04B1/583
摘要： An active hybrid circuit equipped with a resistor bridge, balance network and transmit and receive amplifiers for 2-wire to 4-wire long haul trunk communication between a telephone central office and a distantly located operator console is disclosed. High impedance current sources having voltage follower operational amplifiers are integrated into the hybrid for reducing hybrid bridge loading on the bidirectional 2-wire path while providing adjustable levels of transmission in all directions. One of the high impedance sources is responsive to signals received from the receive amplifier via a bridge resistor for generating output currents to produce desired levels of the received signal on the 2-wire bidirectional path. A second one of the sources is responsive to signals received from the receive amplifier via another bridge resistor for generating currents within the bridge which are opposite to those of the first source and which cancel the receive signal at the input of the transmit amplifier to preclude undesired circulation of that signal back to the operator console.
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公开(公告)号：US4006307A
公开(公告)日：1977-02-01
申请号：US594192
申请日：1975-07-09
摘要： A circuit for reducing transmitted and radiated impulse noise which is generated by opening and closing connections between a transmission path and a source of potential. In the case of closing such a connection a path is connected to a substantially zero potential and the potential is increased to the operating potential over a preset period of time. In the case of opening such a connection the connected potential is decreased to substantially zero over a preset period of time and the path is opened. A potential control circuit is connected between the battery side of the transmission path and the source of potential and the control thereof is coordinated with the connecting means to achieve the described sequences.
摘要翻译： 用于减少通过打开和关闭传输路径和电位源之间的连接而产生的传输和辐射脉冲噪声的电路。 在关闭这种连接的情况下，路径连接到基本上为零的电位，并且在预设的时间段内将电位增加到工作电位。 在打开这种连接的情况下，在预设的时间段内将连接的电位降低到基本为零，并且路径被打开。 电位控制电路连接在传输路径的电池侧和电位之间，并且其控制与连接装置协调以实现所描述的顺序。
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公开(公告)号：US4079210A
公开(公告)日：1978-03-14
申请号：US795941
申请日：1977-05-11
摘要： An electronic program controlled switching system is disclosed having a ringing control circuit for testing called lines for foreign potential and excessive leakage before ringing the called phone. The circuit includes bridge rectifiers and transistor circuitry for checking for foreign potentials and ferrod sensors for detecting undesired leakage. An opto-isolator and relay arrangement controls the application of ringing to the called line. Active filter and latch operational amplifiers sense the application of the ringing and the answering of the rung phone. Magnetic latching relays establish successive test and ringing configurations of the ringing control circuit components under control of a signal distributor and a program controlled processor. Ferrod sensors convey ringing control circuit information to the processor via a scanner.
摘要翻译： 公开了一种电子程控交换系统，其具有振铃控制电路，用于在被叫电话振铃之前测试用于外来电位的呼叫线路和过度泄漏。 该电路包括桥式整流器和用于检查外部电位的晶体管电路和用于检测不期望的泄漏的铁电传感器。 光隔离器和继电器装置控制对被叫线路的振铃应用。 有源滤波器和锁存运算放大器感测到响应和应答梯级电话的应用。 磁存储继电器在信号分配器和程序控制处理器的控制下建立振铃控制电路部件的连续测试和振铃配置。 Ferrod传感器通过扫描仪将振铃控制电路信息传送到处理器。
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