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我所为用户设计的避测系统中,常常由于地形的限制,中心站电台与杨房距离相隔较远,对于电台与机房之间的小信号远距离的传输,以前我们解决的办法是把低频信号送入扩音机,再由扩音机的输出端经过阻抗变压器把信号送到山上电台的MIC口,这种形式有三大缺点: 1.扩音机的输出功率太大,功耗大给系统建设带来不利,特别是在无交流电的情况下。 2.音频输入与功率输出很难调到最佳的工作状态。 3.在发召测指令或通话时,一定要把扩音机电源打开,否则无法召测或通话,工作起来很不方便。基于以上原因,我考虑了一电路,仅采用一块低放集成块,加上一些外围元件和控制电路,就可以较好地克服以上缺点。该电路的工作原理见图1。
I designed for the user to avoid the system, often due to topography restrictions, the central station and the Yang room far apart from the radio and the engine room for small-signal long-distance transmission, we used to solve the low frequency The signal into the megaphone, and then by the amplifier output through the impedance transformer to the MIC station on the mountain radio, this form has three major drawbacks: 1. Amplifier output power is too large, the power consumption of the system to bring adverse, Especially in the absence of AC power. 2. Audio input and power output is difficult to transfer to the best working condition. 3. In the call instruction or call, be sure to open the megaphone power, or can not call or call, work is very inconvenient. For these reasons, I consider a circuit, using only a low-power integrated block, with some external components and control circuit, you can better overcome the above shortcomings. The circuit works shown in Figure 1.