All-digital Mqam Modulation And Demodulation Of A Burst Communication

Information technique plays more and more important role in advanced military fields. It becomes a key factor determining the war victory or defeat. Information warfare is now a main battle form of the modern war. Communications Counter-Measures is a main part of electronic warfare . In order to avoid enemy's communication-scout, Now we used to use false yawp coding, encrypting, spread spectrum, adaptive frequency hopping and control of the power and so on,but have a few of investigate about the directional communication,laser communication and sudden communication. So we bring forward a kind of sudden communication .Our train of thoughts is :deposit a length of original data,code, encrypt and pack it. And the modulator sudden transmit the pack at a random moment. Then the transmitter become silent. In case of the sink gain the sudden information,it should work instantly,and write down the demodulation information,resume the original data. This dissertation adopt the high speed 64QAM modulation and demodulation technology.The transmitter only work in a very short moment,it is slient in most time, so it can avoid enemy's disturb and measure,reduce the chance of be captured; and decrease the transmitter's power, reduce the transmitter's cubage; shorten the channel's time.At first we introduce the Communications Counter-Measures. Generalize the mostly technology about it, and analyze it's develop trend.Chapter 2 studies the continuous and burst 64QAM modulation and demodulation. Chapter 3 is about the important synchronization. In continuous demodulation, time synchronization adopt Gardner estimate arithmetic, carrier wave synchronization adopt the allied estimate of Gardner arithmetic and current loop. In the end, our emulated result prove it is right. In burst demodulation, we adopt immobile special preamble, estimate the preamble, and gain the parameter's estimate. Then complete synchronization of time and carrier wave.Chapter 4 implement the modulation and demodulation of continuous and burst. Present its configuration. Concretely design every module's implement means. Present the picture of the demodulation experiment board. Measure its error,lose. And analyze the experiment result.I am a armyman, and I have never learn communication. So, in order to complete this dissertation , I try to conquer difficulty. In the help of Mr. Cheng ,I study communication basic, and try to do it good. Although this dissertation have not innovation, although this dissertation is not perfect. But I think I have many advancement. It is my basic of my late communication work.