SYNC. ACQUISITION AND TRACKING CIRCUIT FOR DS/ CDMA RECEIVER

摘要

In a sync acquisition and tracking circuit for a DS/CDMA receiver, phase position signals are sequentially and cyclically selected at a specified rate higher than the rate at which Rayleigh fading occurs. The selected signal is used to control the phase of PN sequences. Correlation is taken between spread pilot signals and the orthogonal PN sequences at a chip rate to produce despread pilot signals, which are integrated to produce a correlation value. A set of accumulators are provided, which are sequentially and cyclically selected at the specified rate. The correlation value is applied to the selected accumulator to produce a total sum of correlation values. The highest total sums are selected from the outputs of all accumulators, and corresponding phase position signals are identified. A set of orthogonal despreading sequences are generated corresponding to the identified phase position signals for application to the receiver.