This library computes Infinite Impulse Response Filter.
Filter coefficients, for example, could be evaluate in Matlab (R) and then passed as arguments in the IIR constructor method.
Arduino_RealTime_IIR is a library composed by one class: RT_IIR.
RT_IIR class has a constructor and 3 methods. Uses of this library is very simple:
- create an instance of RT_IIR object defining filter coefficients
- filter each sample of your signal
To make a RT_IIR instance you need to declare a RT_IIR object and then pass the filter parameters to the constructor method:
...
RT_IIR <T> iir = new RT_IIR(b, a, nb, na);
...
Where: b is an array (of type:T, eg: T = double or float) contains numerator coeffs, a is an array (of type:T) contains denominator coeffs, nb is the length of b array, na is the length of a array.
RT_IIR is a template class, so you are allow to filter float or double (or other type) typed samples.
To filter new sample acquired you have to call iir.add(T sample) method as follows:
...
filteredSample = iir.add(sample);
...
iir.add(T sample) add a new sample to the list of samples in processing and computes the filtering operation. This method return the result of the filtering operation.
iir.compute() return the result of filtering operation without any new sample added to the filtering samples queue.
iir.getLastOutput() return the value of the last result obtained by iir.add(T sample) or iir.compute() method.