US 6,633,617 B1 · Device and method for compensating or creating doppler effect using digital signal processing

Abstract

Doppler shift compensation by interpolation of a new sample between successively received signal samples using stored values of an interpolation function. The interpolation function has a non-zero amplitude in an argument range symmetrical about zero argument and zero amplitude outside the range. The time location of a new sample is shifted relative to a pair of received signal samples by an amount corresponding to a Doppler shift. The amplitude of the new sample is computed at a new sample index by combining the pair of received signal samples with corresponding samples of the interpolation function, each corresponding sample of the interpolation function being that sample whose argument is a difference between a corresponding one of the first and second indices and the new sample index. Due to the symmetry properties of the interpolation function, this operation requires as little as two multiply operations and one add operation for each new sample. The interpolation function is generated by performing successive dilations and convolutions of a pulse function.

Claims30

Dependent claims

A method for interpolating between a pair of successively received signal samples of first and second sample indices, respectively, in accordance with a Doppler shift, comprising:

storing plural samples of a correction function in a first argument range symmetrical about zero argument, the function having zero amplitude outside the first argument range;
computing the Doppler shift and determining a time location of a new sample having a new sample index between the pair of received signal samples, the time location being shifted relative to the pair of signal received samples by an amount corresponding to the Doppler shift;
computing an amplitude of the new sample at the new sample index by combining the pair of received signal samples with corresponding samples of the correction function, each corresponding sample of the correction function being that sample whose argument is a difference between a corresponding one of the first and second indices and the new sample index.

A method for compensating for Doppler shift in a received signal comprising:

a) receiving a Doppler shifted signal so as to define the received signal;
b) generating samples of the received signal by sampling the received signal at a system sampling rate;
and
c) generating a Doppler corrected sample using the samples of the received signal by performing the following steps:
(i) determining a Doppler corrected sample index;
(ii) multiplying a sample of the received signal evaluated at a prior sample index by an interpolation function evaluated at a difference between the Doppler corrected sample index and the prior sample index;
(iii) multiplying a sample of the received signal evaluated at a next sample index by the interpolation function evaluated at a difference between the Doppler corrected sample index and the next sample index;
and
(iv) summing the result of steps (ii) and (iii) to provide corrected samples capable of being processed at the system sampling rate to produce a Doppler compensated signal.

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Dependencies are inferred from the claim text.

Device and method for compensating or creating doppler effect using digital signal processing

Life of this patent

Device and method for compensating or creating doppler effect using digital signal processing

Life of this patent

Abstract

Claims30