DSP SPL Directory

The DSP directory contains SPL functions related to digital signal processing (DSP) and Fourier transforms. The directory includes the following SPL files:

ACORR	Calculates the auto-correlation using the convolution method.
ACOV	Calculates the auto-covariance using the convolution method.
AMPSPEC	Calculates normalized complex FFT
AVGFILT	Filters a series using the average of the N neighboring points.
BESTPOW2	Finds the power of 2 greater than or equal to the input value or length of the input series.
BILINEAR	Performs a bilinear transformation with optional frequency prewarping.
BITQUANT	Quantizes an input series to 2^bits levels.
BITSCALE	Converts raw AD counts to scaled engineering values.
CCEPS	Calculates the complex cepstrum.
CLOGMAG	Evaluates the log magnitude of Cascade form coefficients.
COVM	Calculates the covariance matrix of an array.
DCT	Calculates the Discrete Cosine Transform.
DECONV	Performs direct deconvolution in the time domain.
DEMEAN	Removes the mean (or DC value) from a series
DEMODFM	Demodulates an FM waveform using the Hilbert Transform.
EFFBIT	Calculate the number of effective bits possible at a given frequency for a quantizing device.
ENDFLIP	Pads the ends of a series with endpoint reflections.
FACORR	Calculates the auto-correlation using the FFT method.
FACOV	Calculates the auto-covariance using the FFT method.
FCONV	Performs convolution using the FFT method.
FDECONV	Performs deconvolution using the FFT method.
FFTSHIFT	Shifts a 1D or 2D FFT so the 0 frequency is the midpoint.
FILTEQ	Evaluates a Linear Constant Coefficient Difference Equation.
FIRSAMP	Designs an arbitrary FIR filter using frequency sampling.
FREQS	Evaluates the frequency response of a continuous system.
FREQSAMP	Designs a FIR filter from a given magnitude response using the frequency sampling method.
FREQZ	Evaluates the frequency response of a discrete system.
FXCORR	Calculates the cross correlation using the FFT method.
FXCOV	Calculates the covariance using the FFT method.
FZINTERP	Interpolates a series by a factor using FFT zero insertion.
GRPDELAY	Calculates the group delay of a Z transform.
HAMMING	Multiplies a series with a Hamming window.
HANNING	Multiplies a series with a Hanning window.
HILB	Calculates a simple Hilbert transform of a real series.
ICCEPS	Calculates the complex cepstrum.
IDCT	Calculates the Inverse Discrete Cosine Transform.
IMPZ	Calculates the impulse response of a Z transform.
INVFREQS	Calculates analog filter coefficients from a complex frequency response.
INVFREQZ	Calculates digital filter coefficients from a complex frequency response.
INVPSD	Construct a time series from a PSD.
KAISER	Multiplies a series with a Kaiser window.
LINSCALE	Linearly rescales an input series.
LOG2	Returns Log base 2 of the input.
MAGSPEC	Calculates the magnitude of the complex amplitude spectrum
MODFM	Frequency modulate an input series.
NEXTPOW2	Determines the exponent for the next power of 2 greater than or equal to the input value.
NFFT	Calculates an N point FFT via zero padding or time aliasing.
NSPECTRUM	Calculates an N point spectrum via zero padding or time aliasing.
OASFILT	Filters data using the overlap and save method.
PADFILT	FIR filtering with optional endpoint padding.
PHASESPEC	Calculates the phase of the complex amplitude spectrum
POLY	Calculates coefficients of the characteristic polynomial.
POLYSTAB	Stabilizes a denominator polynomial by root reflection.
QUANTIZE	Quantizes an input series to N levels.
RCEPS	Calculates the real cepstrum.
REMOVENA	Removes the NAVALUEs from a series or array.
RESCALE	Linearly rescales an input series.
RESIDUE	Finds the partial fraction expansion of a rational polynomial.
RESIDUEZ	Finds the partial fraction expansion of a Z transform.
SFREQ	Evaluates the frequency response of a continuous system in Hertz.
SHP	Emulates a single pole analog high pass filter.
SLP	Emulates a single pole analog low pass filter.
SONOGRAM	Calculates the 2D Spectrogram as a B&W image.
SPECGRAM	Calculates the 2D Spectrogram as an image.
STARMS	Calculates the short time averaged RMS series.
TF2SS	Calculates the state-space representation
WINFUNC	Multiplies a series with a spectral window.
XCORR	Calculates the cross correlation using the convolution method.
XCOV	Calculates the cross covariance using direct convolution.
ZEROFLIP	Pads the ends of a series with endpoint reflections about 0.0.
ZFREQ	Evaluates the frequency response of a Z transform.
ZINTERP	Interpolates a series to a new sample rate by FFT zero insertion.
ZPFCOEF	Designs a digital filter from a set of analog zeros and poles (S domain).
ZPLANE	Displays a Pole-Zero plot of a Z transform.