- sddsconvolve
`sddsconvolve`()sddsconvolve -- Does FFT convolution, deconvolution, and correlation. Example application: computing the ideal impulse response of a system after you've measured the response to a pulse. - sddsdigfilter
`sddsdigfilter`()sddsdigfilter -- Performs time-domain digital filtering of column data. Example applications: low pass, high pass, band pass, or notch filtering of data to eliminate unwanted frequencies. - sddsfdfilter
`sddsfdfilter`()sddsfdfilter -- Performs frequency-domain filtering of column data. Example application: applying a filter that is specified as a table of attenuation and phase as a function of frequency. - sddsfft
`sddsfft`()sddsfft -- Does Fast Fourier Transforms of column data. Example application: finding signficant frequency components in time-varying data, or finding the integer tune of an accelerator from a difference orbit. - sddsnaff
`sddsnaff`()sddsnaff -- Does Numerical Analysis of Fundamental Frequencies, a more accurate method of determining principle frequencies in signals than the FFT.

Hairong Shang 2017-04-07