Patent ID: 7251268

Claim:
A Rake receiver comprising a radio signal receiving stage, an analogue-to-digital converter (ADC) coupled to the receiving stage, the ADC output being coupled to an input of each of a plurality of parallel signal paths each of the parallel signal paths including signal processing means, combining means for combining outputs from the signal paths and means for recovering symbols from the combined outputs, the receiver further comprising code generation means for generating a filtered pilot code that provides a multibit interpolation of a generated pilot code prior to the parallel signal paths, and the signal processing means in each of the parallel signal paths comprising a variable delay means for delaying a signal in that path by a desired amount and a means for correlating the delayed signal with the filtered pilot code, wherein the signal processing means includes signal deriving means coupled to an output of the code generation means and to the variable delay means for deriving an early-late timing error signal for the signal path, wherein the timing error signal is supplied to means for both adjusting the variable time delay of the variable delay means and for deriving an amplitude and phase of the received signal in the respective signal path, and the timing error signal is further supplied to means for multiplying the delayed signal from the variable delay means by the complex conjugate of the amplitude and phase of the received signal and applying the result to the combining means, characterised in that the code generation means comprises early, on-time and late outputs of the filtered pilot code and the signal deriving means comprises differencing means having inputs connected respectively to the early and late outputs of the code generation means, first and second correlators, each of the first and second correlators having first and second inputs, the first inputs being coupled to the output of the variable delay means and the second inputs being connected respectively to the on-time output of the code generation means and to an output of the differencing means, the first correlator having an output for the amplitude and phase of the received signal in the signal path and the second correlator having an output for the early-late timing error signal.