Research Of Digital AGC And Related Technologies

The thesis mainly focuses on the research of AGC (Automatic Gain Control) algorithms that are able to relieve the pressure of requirement of larger dynamic range in ADC device in modern wireless communication systems, especially in LAS-CDMA system. Firstly, overviews of the development process of mobile communications and the introduction of LAS-CDMA system are shown in the first part of the thesis.Secondly, it is seen that the pressure of dynamic range on the wireless transceiver is becoming more and more heavier and the reasons are listed. As an effective way to improve the dynamic range performance, AGC technology is introduced. And some analyses, including theory analysis, sorting methods, performance deduction and etc, about AGC and related AGC technology will also be found in this part.Thirdly, after discussing in the theory of AGC and ADC, some AGC algorithms in LAS-CDMA system, including pilot based AGC algorithm, chip based fast AGC algorithm, multiple ADC extension scheme and peak-value-array based AGC algorithm, are given. All the information of the schemes simulations and analyses about them is presented in words and diagrams. In the front of this part are the depictions about analyses and derivation of AGC technology realization and dynamic range of attenuation signals in LAS-CDMA system.Fourthly, some other technologies, including nonlinear quantify, self-adapting technology and dither, to enhance dynamic range of ADC are brought forward. They can make more improvement in LAS-CDMA if integration with above AGC algorithms.Finally, summarization of the thesis and prospect of AGC and related technologies are shown in the final part.