Patent ID: 7099402
Filing Date: 2006-08-29
Classification: H04B

Abstract:
1. A system for processing of a complex baseband signal having a signal content for signal transmission from a wireless communication system, the wireless communication system having a data rate, the system comprising: an intermediate frequency based complex-to-real up-converter configured to digitally sample the complex baseband signal at a sample frequency with a sample frequency value, FS, and configured to digitally sample with one or more periodic functions of an intermediate frequency having an intermediate frequency value, FIF, to convert the complex baseband signal into a real digital signal having digital signal representations with each digital signal representation sized in width along a frequency spectrum substantially equal to a bandwidth, W, and containing substantially the signal content of the complex baseband signal, the digital signal representations having frequencies such that the digital signal representations are spaced along the frequency spectrum in pairs with a mid-position of the bandwidth, W, of each digital signal representation of each pair being displaced, by approximately the intermediate frequency value, either positively or negatively, on either side of one of a plurality of frequencies on the frequency spectrum, each of the plurality of frequencies being equal to a product of an integer multiplied by approximately the sample frequency value; and an intermediate frequency based bandpass filtering digital-to-analog converter being a noise shaped digital-to-analog converter configured to convert the real digital signal into an analog signal having analog signal representations, each sized in width along the frequency spectrum substantially equal to the bandwidth, W, and having substantially the signal content of the complex baseband signal, the analog signal representations being spaced along the frequency spectrum at intervals and frequencies corresponding to the digital signal representations, the analog signal further including noise segments located along the frequency spectrum between the analog signal representations, the intermediate frequency based bandpass filtering digital-to-analog converter having a noise floor with low-noise areas sized in width greater than or substantially equal to the bandwidth, W, and spaced along the frequency spectrum in pairs with each low-noise area of each pair being displaced along the frequency spectrum at intervals and frequencies corresponding to the digital signal representations, the noise floor further including high-noise areas between the low-noise areas.