Nordic Semiconductor ASA
MATCHED-FILTER RADIO RECEIVER

Abstract:

A digital radio receiver has a matched filter bank of filter modules for receiving phase- or frequency-modulated radio signals. Each module cross-correlates a sampled signal with a respective multi-symbol filter sequence, using a plurality of samples in each symbol period. The matched filter bank calculates first values (z.sub.n(1)), for respective symbol periods, of a cross-correlation of the sampled signal with a first complex exponential function defined at sample points over one symbol period, and calculates second values (z.sub.n(-1)), for the respective symbol periods, of a cross-correlation of the sampled signal with a second, different, complex exponential function. A set of the filter modules cross-correlates the sampled signal with their respective filter sequences using an algorithm that takes, as input, the first values (z.sub.n(1)) for symbol periods at which the respective filter sequence has a first value, and the second values (z.sub.n(-1)) for symbol periods at which the filter sequence has a second, different, value.