本文介绍的电话机通话无线发射器,可将通话过程中的语言信号变成射频信号发射,以便用录音机或 FM 收音机监听通话。这种发射器有两种无线发射方式。第一种为电话机通话微型无线电发射器,电路原理如图1所示。因为输入口 CN1串接于电话线路与电话机之间,所以在R1两端既有交换机发出的直流电压降,也有通话的语言信号。这两种电压经 DD1极性转换为直流电压,给 T1组成的考毕兹振荡电路供电,电阻 R2和 R3给 T1提供适当的偏置电流以使其工作 This article describes the telephone call wireless transmitter, the speech signal during the call into a radio frequency signal transmission, in order to use the recorder or FM radio to monitor the call. This transmitter has two ways of wireless transmission. The first is a telephone transmitter miniature radio transmitter, the circuit shown in Figure 1. Because the input port CN1 is connected in series between the telephone line and the telephone set, there is a DC voltage drop at the two ends of the R1 and a speech signal of the call. These two voltages are converted to DC voltage by the polarity of DD1 to power the Colpitts oscillator circuit consisting of T1. Resistors R2 and R3 supply the appropriate bias current to T1 to operate