Using statistics to locate signals in noise
First Claim
1. A computer readable storage medium for providing a digital signal to a digital data processor, said digital signal, when executed on said digital data processor, controlling said data processor to perform steps offiltering noise from an original signal to produce a filtered signal,performing a phased subtraction or addition of said filtered signal from or to said original signal or vice-versa to produce a noise signal,computing variance of an autocorrelation of said noise signal over at least a first period and a second period of said noise signal, said first period and said second period being of equal duration, andcontrolling at least one of storage and compression of said noise signal based on a result of said step of computing variance of an autocorrelation.
0 Assignments
0 Petitions
Accused Products
Abstract
Computation of variance or variance of the autocorrelation over a moving window of various sizes of a signal containing noise and possibly a small digital signal provides a sensitive, frequency independent indication of the likelihood of the presence of a small pulse, chirp or even spread spectrum digital signal possibly obscured by noise or larger signals in the signal to much lower signal-to-noise ratios than previously possible. Large signals in the signal which may also obscure any small signal are removed to a different signal path from the noise and small signals by subtraction after compression and reconstruction of the large signal. The compression noise thus added to the signal may also increase sensitivity of the variance of the autocorrelation to small signals obscured by the large signals. Controlling storage in response to the computed variance or variance of the autocorrelation allows substantial avoidance or limitation of storage of signals which contain only noise.
11 Citations
11 Claims
-
1. A computer readable storage medium for providing a digital signal to a digital data processor, said digital signal, when executed on said digital data processor, controlling said data processor to perform steps of
filtering noise from an original signal to produce a filtered signal, performing a phased subtraction or addition of said filtered signal from or to said original signal or vice-versa to produce a noise signal, computing variance of an autocorrelation of said noise signal over at least a first period and a second period of said noise signal, said first period and said second period being of equal duration, and controlling at least one of storage and compression of said noise signal based on a result of said step of computing variance of an autocorrelation.
-
3. A method of reducing storage or compression of a signal which is unlikely to contain a small data signal, said method comprising
providing a program to a data processor, said program being capable of configuring said data processor to provide: -
a filter for filtering noise from an original signal to produce a filtered signal, a calculator for performing a phased subtraction or addition of said filtered signal from or to said original signal or vice-versa to produce a noise signal, a statistical calculator for computing variance of an autocorrelation of said noise signal over at least a first period and a second period of said noise signal, said first period and said second period being of equal duration, and a storage medium or a controllable compression arrangement for performing at least one of storage and compression of said noise signal responsive to said statistical calculator providing a result of said step of computing variance of an autocorrelation. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11)
-
Specification