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一、概述在长途自动交换和市内自动交换的局间记发机信号——多频互控信号中,需要大量的线性电子电路。这些电路目前多数采用分立元件和LC滤波器构成。由于电平调节放大器的压缩范围不够大、调节速度慢,在高电平信号输入时、容易产生二次交调信号、造成误动引起错号。另外、LC滤波器体积大、调试复杂、价钱昂贵,在调节放大与接收器中大量使用阻抗匹配变压器、也带来了生产工艺上的复杂性。在SH-1型万门纵横制中我们选用运算放大器做成音频放大和有源滤
I. Overview In the long-distance automatic exchange and automatic exchange of the city between the office machine recording signal - multi-frequency mutual control signals, the need for a large number of linear electronic circuits. Most of these circuits use discrete components and LC filters. As the level adjustment amplifier compression range is not big enough, the slow adjustment speed, high-level signal input, easy to produce a second intermodulation signal, causing misoperation caused the wrong number. In addition, LC filter volume, debugging complex, expensive, in the regulation of amplification and receiver to use a large number of impedance matching transformer, but also brought the complexity of the production process. In the SH-1-type Vanguard system we use op amp made of audio amplification and active filter