DADiSP Online Help
Click here to see this page in full context
DADiSP Worksheet Functions > Function Categories > Fourier Transforms and Signal Processing > ZEROFLIP
Pads the ends of a series with endpoint reflections about 0.0.
ZEROFLIP(series, padlen)
|
series |
- |
An input series or array. |
|
padlen |
- |
Optional. An integer, the length of segment with which to pad. Defaults to |
A series.
W1: integ(gnorm(1000,1/1000))
W2: zeroflip(W1, 200); overp(W1, lred)
The simulated data in W1 is padded at the beginning and end with segments of length 200 that are reflections of the beginning and end segments about 0. The original data is overplotted to provide a comparison.
ZEROFLIP is useful in FIR filtering operations where the input data is padded at the beginning and end to diminish the ramp up and ramp down transients implicit in the filtering process. The transients occur because the input data is assumed to be zero prior to the start and after the end of the data. See PADFILT and FPADFILT for more information.