SPKitResonator


User's Guide

SPKitResonator a second order all-pole (IIR) band-pass filter. It implements a setCenterFreqAndBW(SPKitFloat f, SPKitFloat bw) function for setting the filter center frequency to f and bandwidth (in cycles per second) to bw.

See also SPKitBWBandPassFilter.

For a more detailed description of the resonator, see Dodge & Jerse (1985:186-189).


Programmer's Reference

Defined in <spkit/resonato.h>
Inherits from SPKitProcessor

SPKitResonator implements a setCenterFreqAndBW() function for setting the filter center frequency and bandwidth. It also overrides setInput().

Public Members

SPKitError setInput(SPKitProcessor* newInput)
connect an input to the object and initialize it. Allocates a delay buffer for each audio channel of the input object.

Calls SPKitProcessor::setInput().

void setCenterFreqAndBW (SPKitFloat f, SPKitFloat bw)
set filter centerFreq to f and bandwidth to bw. The parameters are in cycles per second.

The function calculates the filter coefficients according to the filter center frequency, bandwidth and sampling rate ( inputSamplingRate).

Public Members

SPKitFloat centerFreq
the filter center frequency
SPKitFloat bandwidth
the filter bandwidth
SPKitFloat a0
coefficients for the current input and previously read samples. Set by setCenterFreqAndBW() to scale the amplitude of the output signal to a midband gain of one.
SPKitFloat b1
coefficients for a previous output sample
SPKitFloat b1
coefficients for a previous output sample
SPKitSampleBuffer* chBuf[]
buffers for previous output samples

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Kai Lassfolk / University of Helsinki / kpl@elisir.helsinki.fi