摘要
对于公用电话网上的专用Ｍｏｄｅｍ，其外部混合电路极大地影响着数据通信的质量。本文对在该电路中如何利用变压器实现阻抗匹配以及运放电路的设计进行了讨论。
The quality of data communication for the special modem on PSTN is greatly influenced by its external hybrid circuit. The paper expatiates on how to achieve impedance matching with a transformer and how to design an operational amplifier circuit.
