# Frequency response of continuous wavelet transform filters

### Description

Returns the frequency response of a continuous wavelet filter. The choices for filters are limited to Haar, Gaussian, and Morlet families.

### Usage

1 2 |

### Arguments

`frequency` |
a numeric vector denoting the frequencies (in rad/sec) over which the
frequency response function for the specified wavelet should be evaluated.
Default: |

`shift` |
the frequency shift |

`times` |
a numeric vector of values corresponding to times at which the
specified filter should be evaluated. If not |

`variance` |
the variance of a Gaussian PDF. Used only for the (derivatives of) Guassian filters.
Default: |

`wavelet` |
a character string denoting the wavelet filter.
Choices are "haar", "gaussian1", "gaussian2", and "morlet",
where |

### Value

the frequency response corresponding to the input frequencies.

### References

D. B. Percival and A. T. Walden, *Wavelet Methods for
Time Series Analysis*, Cambridge University Press, 2000.

### See Also

`wavCWT`

.

### Examples

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 | ```
## set the plot grid
old.plt <- splitplot(2,2,1)
## create a frequency vector
w <- seq(-10,10,length=1000)
## calculate the frequency responses for various
## mother wavelets and plot the results
wavelets <- c("haar", "gaussian1", "gaussian2", "morlet")
for (i in seq(wavelets)){
if (i > 1) splitplot(2,2,i)
filt <- wavelets[i]
plot(w, abs(wavCWTFilters(wavelet=filt, frequency=w)),
ylab="|Psi(w)|", xlab="frequency", type="l")
title(filt)
}
par(old.plt)
``` |