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无线电广播是利用无线电波传播信息的。虽然我们看不到无线电波,但它确确实实存在我们周围的空间里。如何把无线电广播信号变为我们能听到的声音呢? 图1是一个最简单收音机的电原理图。线圈L和可变电容器C组成一个调谐电路,它能从天线接收下来的许多信号中选择一个需要的电台信号,再通过二极管的检波把高频载波中携带的音频信号取出,由耳机把音频电流转变为声音。由于这个电路中没有放大器,所以要架设良好的天线
Radio is the use of radio waves to disseminate information. Although we can not see the radio waves, it does exist in the space around us. How to turn a radio signal into something we can hear? Figure 1 shows the electrical schematic of one of the simplest radios. The coil L and the variable capacitor C form a tuning circuit which can select a desired radio signal from many signals received by the antenna and then remove the audio signal carried in the high frequency carrier by the diode detection. Turn into sound. Since there is no amplifier in this circuit, a good antenna should be set up