Design And Implementation Of Maglev Vehicles To Communication Systems If Demodulator

The radio-communication is used widely today. The technology of Modulator-Demodulator as one important part of radio-communication has been researched widely too. According to "The 38GHz Communication System of Maglev Train", this paper focus on the research of multi-channel and multifunctional IF demodulator on the base of some concepts about modulator. We must modulate the carrier wave by digital signals if we want to transmit the digital signals. It is called binary digital modulator when the modulate signal is binary signal. The frequency modulation is one of the most important modulation it is used widely in communication, broadcast, telemetry and so on. The frequency range is very broad which contains middle-shortwave, super-shortwave and microwave. There are two different frequency modulation according to the modulated signal. One is analog frequency modulation, the other is digital frequency modulation. And there are also two methods for recovering the demodulating signal.The technology of frequency demodulator is not very complex, so this paper is mostly discussed about how to design an actual circuit according to the system's target. The paper begins with the analysis of power spectral density, then I introduce some important methods and concepts relate to modulation and demodulation. And I have done some work to compare the different demodulation technology. In the end, I show the details about the circuit. So this paper has some useful engineering significance.At the last, you can find the principle diagram and the circuit. And I also give some analysis about the result of test.