A Study On Audio Frequency Data's Condensation And Modulation Communication Based On Wavelet Analysis

In all kinds of complicated network, oriented linking and unlinking, communication frequency resource is strained, and bandwith to transmitting audio frequency signal is too restricted, complicated and fluky, while audio frequency data exponential have been increased in the last several years. Under the circumstances, based on the research of predecessor, this paper studies wavelet analysis's maths gist and practices significance on signal process, and puts forward a optimized wavelet package condensation arithmetic to process audio frequency data, which gives attention to coding efficiency, multirate and compression delay. Simulation experiment on the arithmetic has been done by MATLAB. Comparing with all kinds of experiment results on vary audio-data and wavelet function, the arithmetic has effect on condensation to realize real-time coding and decoding in multirate circumstance with a degree of calculating complexity. With the support of hardware devices such as DSP chip, this arithmetic has effective application on complicated practice source coding. This paper alse applies wavelet to multicarrier modem/demodem transfer. The use of the induced wavelet package improves this arithmetic to search best wavelet package basis, and boosts up the support to multirate. The experiment's result approves arithmetic effective. The problem in this paper has been answered in chapter 1. Data compression is an old problem and a lot of research has been done on it, but it is still worth studying, especially in the current circumstances where network and information technologied developed in high speed. In chapter 2, some previous compression arithmetics are analyzed in arithmetic structure and maths reasoning. Comparing each arithmetic, merits have been reserved and defects have been abandoned. Meanwhile, special process and general dealing of autio-signal have been analyzed, which provide bases to improve old compression arithmetic. Wavelet analysis and wavelet transfer is the emphases of the paper, which is in chapter 3. Enumerating many common wavelet functions, writer analyzes maths signification and practices signification in essence with stress on composing and decomposing of multi- sampling filter. Based on anatomy of compression arithmetic on wavelet and wavelet package, optimized wavelet package condensation arithmetic has been brought forward in chapter 4, which is more adapted for multirate coding and decoding. Many simulation experiments have been done, and result is invigorated. Not only some modem schemes but also conception of induted wavelet are presentationed in chapter 5. Most closing optimized arithmetic of choosing wavelet package basis is put forward, and experiment using the arithmetic is performed in brief and unrealistic channel. Though the experiments have proved the arithmetic significant in theory, practical systems differ in thousands ways and are too anfractuous to simulate. Furthermore, even in theory, many limits and defects exist in this arithmetic, so further research should be done on the topic.