![]() The two members of this structure directPath and delayedPath are arrays of IIR::Coefficients, made of polyphase second order allpass filters and an additional delay in the second array, that can be used in cascaded filters processed in two parallel paths, which must be summed at the end to get the high order efficient low-pass filtering. The result is a IIRPolyphaseAllpassStructure object. This method generates arrays of IIR::Coefficients for a low-pass filter, with a cutoff frequency at half band, using an algorithm described in the article "Digital Signal Processing Schemes for efficient interpolation and decimation" from Pavel Valenzuela and Constantinides. ![]() This method returns an array of IIR::Coefficients, made to be used in cascaded IIR::Filters, providing a minimum phase low-pass filter with ripples in both the pass band and in the stop band.ĭesignIIRLowpassHalfBandPolyphaseAllpassMethod (FloatType normalisedTransitionWidth, FloatType stopbandAmplitudedB) This method returns an array of IIR::Coefficients, made to be used in cascaded IIRFilters, providing a minimum phase low-pass filter without any ripple in the pass band only.ĭesignIIRLowpassHighOrderEllipticMethod (FloatType frequency, double sampleRate, FloatType normalisedTransitionWidth, FloatType passbandAmplitudedB, FloatType stopbandAmplitudedB) This method returns an array of IIR::Coefficients, made to be used in cascaded IIRFilters, providing a minimum phase low-pass filter without any ripple in the stop band only.ĭesignIIRLowpassHighOrderChebyshev2Method (FloatType frequency, double sampleRate, FloatType normalisedTransitionWidth, FloatType passbandAmplitudedB, FloatType stopbandAmplitudedB) ![]() This method returns an array of IIR::Coefficients, made to be used in cascaded IIRFilters, providing a minimum phase high-pass filter without any ripple in the pass band and in the stop band.ĭesignIIRLowpassHighOrderChebyshev1Method (FloatType frequency, double sampleRate, FloatType normalisedTransitionWidth, FloatType passbandAmplitudedB, FloatType stopbandAmplitudedB) This method returns an array of IIR::Coefficients, made to be used in cascaded IIRFilters, providing a minimum phase low-pass filter without any ripple in the pass band and in the stop band.ĭesignIIRLowpassHighOrderButterworthMethod (FloatType frequency, double sampleRate, int order)ĭesignIIRHighpassHighOrderButterworthMethod (FloatType frequency, double sampleRate, int order) This method generates a FIR::Coefficients for a low-pass filter, with a cutoff frequency at half band, using an algorithm described in the article "Design of Half-Band FIR Filters for Signal Compression" from Pavel Zahradnik, to get an equiripple like high order FIR filter, without the need of an iterative method and convergence failure risks.ĭesignIIRLowpassHighOrderButterworthMethod (FloatType frequency, double sampleRate, FloatType normalisedTransitionWidth, FloatType passbandAmplitudedB, FloatType stopbandAmplitudedB) This method generates a FIR::Coefficients for a low-pass filter, by minimizing the average error between the generated filter and an ideal one using the least squares error criterion and matrices operations.ĭesignFIRLowpassHalfBandEquirippleMethod (FloatType normalisedTransitionWidth, FloatType amplitudedB) This method is also a variant of the function designFIRLowpassWindowMethod, using a rectangular window as a basis, and a spline transition between the pass band and the stop band, to reduce the Gibbs phenomenon.ĭesignFIRLowpassLeastSquaresMethod (FloatType frequency, double sampleRate, size_t order, FloatType normalisedTransitionWidth, FloatType stopBandWeight) This a variant of the function designFIRLowpassWindowMethod, which allows the user to specify a transition width and a negative gain in dB, to get a low-pass filter using the Kaiser windowing function, with calculated values of the filter order and of the beta parameter, to satisfy the constraints.ĭesignFIRLowpassTransitionMethod (FloatType frequency, double sampleRate, size_t order, FloatType normalisedTransitionWidth, FloatType spline) ![]() This method generates a FIR::Coefficients for a low-pass filter, using the windowing design method, applied to a sinc impulse response.ĭesignFIRLowpassKaiserMethod (FloatType frequency, double sampleRate, FloatType normalisedTransitionWidth, FloatType amplitudedB) WindowingMethod = typename WindowingFunction::WindowingMethodĭesignFIRLowpassWindowMethod (FloatType frequency, double sampleRate, size_t order, WindowingMethod type, FloatType beta=static_cast(2)) IIRCoefficients = typename IIR::Coefficients More.įIRCoefficientsPtr = typename FIR::Coefficients::Ptr The structure returned by the function designIIRLowpassHalfBandPolyphaseAllpassMethod. This class provides a set of functions which generates FIR::Coefficients and IIR::Coefficients, of high-order low-pass filters. ![]()
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