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wnoise

Noisy wavelet test data

Syntax

Description

X = wnoise(FUN,N) returns values of the test signal given by FUN, on a 2N grid of [0,1].

[X,XN] = wnoise(FUN,N,SQRT_SNR) returns a test vector X as above, rescaled such that std(X) = SQRT_SNR. The returned vector XN contains the same test vector corrupted by additive Gaussian white noise N(0,1). Then, XN has a signal-to-noise ratio of SNR = (SQRT_SNR)2.

[X,XN] = wnoise(FUN,N,SQRT_SNR,INIT) returns previous vectors X and XN, but the generator seed is set to INIT value.

The six functions below are due to Donoho and Johnstone (See "References").

FUN = 1     or
'blocks'
FUN = 2     or
'bumps'
FUN = 3     or
'heavy sine'
FUN = 4     or
'doppler'
FUN = 5     or
'quadchirp'
FUN = 6     or
'mishmash'

Examples

See Also
wden

References

Donoho, D.L.; I.M. Johnstone (1994), "Ideal spatial adaptation by wavelet shrinkage," Biometrika, vol 81, pp. 425-455.

Donoho, D.L.; I.M. Johnstone (1995), "Adapting to unknown smoothness via wavelet shrinkage via wavelet shrinkage," JASA, vol 90, 432, pp. 1200-1224.


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