| Digital power amplifier technique appears to be a new technique with modern digital technique developing. The power using efficiency of digital power amplifier is up to 90% while that of traditional analog power amplifier is between 20% and 60%, generally, as usual. However, fidelity of digital power amplifier is less than traditional analog power amplifier. Therefore, recent researches lay more stress on how to improve the fidelity of digital power amplifier.The difficultis of broadband matching technique are that load impedance varies with frequency and it can't be expressed with an analytical expression. Hence, it is difficult to realize ideal matching network in practice. Although some impedance matching methods have beed found, broadband matching technique has not been solved well.In this dissertation, the class D digital power amplifier technique is analyzed in detail on base of summarizing analog power amplifier technique simply. How to develop a digital power amplifier, and how to improve fidelity of digital power amplifier on using new modulation technique are discussed. Experience proves the fidelity of digital power amplifier is better using adaptive carrier wave modulation technique than using fixed carrier wave modulation technique. In The dissertation, the concept of impedance matching is expounded. Impedance matching is divided into resistance matching and reactance matching. Aiming at resistance matching technique, two kinds of signal generator equalization algorithm are developed. One is the opened loop and the other is closed loop. Algorithm is analyzed in detail, and an algorithmic analytical expression is educed. Than the computer simulation and pool experiment are done. The result of experiment is consistent with the result of simulation. It proves that the two kinds of signal generator equalization algorithm are effective on achieving broadband resistance matching compensation. |
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