Adaptive weak signal identification system
First Claim
1. An adaptive weak signal identification system for identifying a weak signal of interest present in a given bandwidth along with a strong interference signal which is at a different frequency, comprising:
- a. a first Fast Fourier Transform circuit for performing a Fast Fourier Transform on a discrete block of data points of an input data signal;
b. a filter coefficient generator means, coupled to the output of said Fast Fourier Transform circuit, for identifying the frequency of the strong interference signal, and for generating filter coefficients for a notch filter based upon the frequency of the strong interference signal;
c. said notch filter, having said generated filter coefficients as an input and further having the input data signal as an input, for performing a notching filtering operation on the input data signal;
d. a second Fast Fourier Transform circuit, coupled to the output of the notch filter, for performing a Fast Fourier Transform on the output of said notch filter;
e. means, coupled to the output of the Fast Fourier Transform circuit, for identifying the frequency of the weak signal of interest.
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Abstract
An adaptive weak signal identification system having a simple implementation which is capable of rapidly tracking weak signals with time varying frequencies in the presence of a strong interference signal. The system includes a first Fast Fourier Transform circuit for performing a Fast Fourier Transform on a discrete block of data points of an input data signal. A filter coefficient generator is coupled to the output of the Fast Fourier Transform circuit, and identifies the frequency of the strong interference signal, and then based thereon generates filter coefficients for a notch filter. A notch filter receives the generated filter coefficients, and further has the input data signal as an input, on which it performs a notch filtering operation to dramatically reduce the intensity of the interference signal. A second Fast Fourier Transform circuit then performs a Fast Fourier Transform on the output passed by the notch filter, and the output of the Fast Fourier Transform circuit is analyzed to identify the frequency of the weak signal of interest.
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Citations
14 Claims
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1. An adaptive weak signal identification system for identifying a weak signal of interest present in a given bandwidth along with a strong interference signal which is at a different frequency, comprising:
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a. a first Fast Fourier Transform circuit for performing a Fast Fourier Transform on a discrete block of data points of an input data signal; b. a filter coefficient generator means, coupled to the output of said Fast Fourier Transform circuit, for identifying the frequency of the strong interference signal, and for generating filter coefficients for a notch filter based upon the frequency of the strong interference signal; c. said notch filter, having said generated filter coefficients as an input and further having the input data signal as an input, for performing a notching filtering operation on the input data signal; d. a second Fast Fourier Transform circuit, coupled to the output of the notch filter, for performing a Fast Fourier Transform on the output of said notch filter; e. means, coupled to the output of the Fast Fourier Transform circuit, for identifying the frequency of the weak signal of interest. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification