# Digital Filtering

Use digital filtering to remove unwanted parts of a digital signal such as noise. LabWindows/CVI provides both finite impulse response (FIR) and infinite impulse response (IIR) filters.

The LabWindows/CVI Advanced Analysis Library includes the following digital filtering functions:

Function | Description
--- | ---
AllocIIRFilterPtr | Allocates and initializes the filter information structure, which is used with the IIR cascade filter coefficient design calls.
Bessel_CascadeCoef | Generates the set of cascade form filter coefficients to implement an IIR filter as specified by the Bessel filter model.
Bessel_Coef | Generates the set of filter coefficients to implement an IIR filter as specified by the Bessel filter model.
Bw_BPF | Filters the input array using a Butterworth bandpass digital filter.
Bw_BSF | Filters the input array using a Butterworth bandstop digital filter.
Bw_CascadeCoef | Generates the set of cascade form filter coefficients to implement an IIR filter as specified by the Butterworth filter model.
Bw_Coef | Generates the set of filter coefficients to implement an IIR filter as specified by the Butterworth filter model.
Bw_HPF | Filters the input array using a Butterworth highpass digital filter.
Bw_LPF | Filters the input array using a Butterworth lowpass digital filter.
CascadeToDirectCoef | Converts from cascade IIR coefficients to direct-form IIR coefficients.
Ch_BPF | Filters the input array using a Chebyshev bandpass digital filter.
Ch_BSF | Filters the input array using a Chebyshev bandstop digital filter.
Ch_CascadeCoef | Generates the set of cascade form filter coefficients to implement an IIR filter as specified by the Chebyshev filter model.
Ch_Coef | Generates the set of filter coefficients to implement an IIR filter as specified by the Chebyshev filter model.
Ch_HPF | Filters the input array using a Chebyshev highpass digital filter.
Ch_LPF | Filters the input array using a Chebyshev lowpass digital filter.
Elp_BPF | Filters the input array using an elliptic bandpass digital filter.
Elp_BSF | Filters the input array using an elliptic bandstop digital filter.
Elp_CascadeCoef | Generates the set of cascade form filter coefficients to implement an IIR filter as specified by the elliptic (or Cauer) filter model.
Elp_Coef | Generates the set of filter coefficients to implement an IIR filter as specified by the elliptic (or Cauer) filter model.
Elp_HPF | Filters the input array using an elliptic highpass digital filter.
Elp_LPF | Filters the input array using an elliptic lowpass digital filter.
Equi_Ripple | Designs a multiband FIR linear phase filter, a differentiator, or a Hilbert Transform using the Parks-McClellan algorithm.
EquiRpl_BPF | Designs an optimal bandpass FIR linear phase filter using the Parks-McClellan algorithm.
EquiRpl_BSF | Designs a bandstop FIR linear phase filter using the Parks-McClellan algorithm.
EquiRpl_HPF | Designs an optimal highpass FIR linear phase filter using the Parks-McClellan algorithm.
EquiRpl_LPF | Designs an optimal lowpass FIR linear phase filter using the Parks-McClellan algorithm.
FIR_Coef | Generates a set of FIR filter coefficients based on the window design method.
FreeIIRFilterPtr | Frees the IIR cascade filter structure and all internal arrays.
IIRCascadeFiltering | Filters the input sequence using the specified cascade IIR filter.
IIRFiltering | Filters the input sequence using the specified IIR filter.
InvCh_BPF | Filters the input array using an inverse Chebyshev bandpass digital filter.
InvCh_BSF | Filters the input array using an inverse Chebyshev bandstop digital filter.
InvCh_CascadeCoef | Generates the set of cascade form filter coefficients to implement an IIR filter as specified by the inverse Chebyshev filter model.
InvCh_Coef | Generates the set of filter coefficients to implement an IIR filter as specified by the inverse Chebyshev filter model.
InvCh_HPF | Filters the input array using an inverse Chebyshev highpass digital filter.
InvCh_LPF | Filters the input array using an inverse Chebyshev lowpass digital filter.
Ksr_BPF | Designs a digital bandpass FIR linear phase filter using a Kaiser window.
Ksr_BSF | Designs a digital bandstop FIR linear phase filter using a Kaiser window.
Ksr_HPF | Designs a digital highpass FIR linear phase filter using a Kaiser window.
Ksr_LPF | Designs a digital lowpass FIR linear phase filter using a Kaiser window.
ResetIIRFilter | Resets the internal filter state information to zero before the next cascade IIR filtering operation.
WindFIR_Filter | Generates windowed FIR filter coefficients.