Wideband channel sounding dynamic range using a sliding correlator

The sliding correlator is widely used in channel sounders employed to measure the impulse response of the radio channel. Cross-correlation of two pseudonoise (PN) sequences with slightly different chip rates gives the channel impulse response. However, the slight difference in chip rates creates various distortions in the cross-correlation response, compared with the autocorrelation function of the same PN sequence. The most significant of these is a reduction in dynamic range. Using a novel algorithm, this paper quantifies the dynamic range as a function of N (the PN sequence length) and k (the time scaling factor, or the inverse of the fractional difference in chip rates), allowing a sliding correlator with up to N=2047, and k=100000 to be fully simulated. A design method based on the results presented in the paper is described.