FIRFilter initialization

[m0rphex]

Hi thanks for the library. Testing the Butterworth worked great with i2s audio and the ESP32.
I would like to test coefficients with the FIRFilter, but having trouble initiating the filter and there isn't an example for it currently, at least I haven't found one.
Something like auto filter = FIRFilter<TAP_COUNT, uint16_t>(&filter_taps) doesn't work. I'm aware that the notch filter makes use of the FIRFilter, but I can't wrap my head around how to get a simple FIR filter object initialized.
An example would be great!

[tttapa]

What is the type of filter_taps? The FIRFilter class expects the argument to be of type Array<uint16_t, TAP_COUNT>.

Apart from the documentation, you can always have a look at the tests to learn how to initialize the different classes:

Arduino-Filters/test/Filters/test-FIRFilter.cpp

Line 31 in 4b4cc09

FIRFilter<11, int> filter = {{1, 2, 3, -4, -4, 5, 6, 1, 2, 1, -2}};

The current implementation of FIRFilter uses the same type for the accumulator as for the inputs and the coefficients. If you're working with integers, it might be better to use a larger type for the accumulator, especially with high tap counts. I might add this option to the library in a future release.

[m0rphex]

Thank you for the prompt response and pointing out the example, I got my test application working. I had the type wrong, used int finally for a low pass filter. I'm making a sdr receiver with the ESP32-A1S kit (hopefully module later) and would like to implement a FIR low pass filter with a +-45 degree Hilbert transform but I have still a lot to learn. Your Butterworth filter sounds great and I'm able to sample at 192000 Hz with dma buffers. I will also experiment with applying a phase shift to the i q channels after the Butterworth filtering and before summing them. DSP is fun but the learning curve is quite steep :) Thank you again!