Study of the effects of signal filtering on acousto-optic correlator performance

The performance of acousto-optic correlators (AOC) in spread-spectrum receivers is considered. The received pseudorandom sequences are correlated with reference ones in an acousto-optic cell. In particular, the effects of receiver filtering on the AOC processing gain are analyzed in the presence of additive white Gaussian noise (AWGN). The signal processing method is presented. For ideal AOCs, simple analytical expressions are derived for two different types of receiver filters: ideal and RC first-order filters. The results are given in terms of the ratio beta of the code rate to the filter bandwidth. They show approximate processing gain losses of 4 dB for the first type and 1 dB for the second type for beta = 5. For real AOCs, the results are obtained from numerical simulation. (c) 2006 Society of Photo-Optical Instrumentation Engineers.