Minimizing power consumption in direct sequence spread spectrumcorrelators by resampling IF samples-Part I: performance analysis

摘要

Most modern digital receivers sample the received RF signal at annintermediate frequency (IF), then downconvert to the baseband in thendigital domain. The baseband samples are subsequently correlated with antime-limited square pulse, which is readily implemented as annintegrator. Since correlation is performed at the sampling frequency,nthe receiver correlates at an unnecessarily high frequency. This highnfrequency results in significant power dissipation especially ifnparallel correlators are employed. By downsampling after appropriatenfiltering to slightly above the signal Nyquist rate, correlation isnachieved at a fraction of the sampling frequency, resulting inncorresponding reduction in power consumption. Furthermore, by resamplingnto an integer number of samples per chip, architectural changes in thencorrelators are possible, allowing even more reduction in powernconsumption. In this paper, a resampling correlator with minimalnhardware overhead that outperforms the conventional correlator isnpresented