How to implement low pass filter using java

Question

I am trying to implement a low pass filter in Java. My requirement is very simple,I have to eliminate signals beyond a particular frequency (Single dimension). Looks like Bu

Answer 1

I have designed a simple butterworth function recently (http://baumdevblog.blogspot.com/2010/11/butterworth-lowpass-filter-coefficients.html). They are easy to code in Java and should be fast enough if you ask me (you'd just have to change filter(double* samples, int count) to filter(double[] samples, int count), I guess).

The problem with JNI is that it costs platform independence, may confuse the hotspot compiler and the JNI method calls within your code may still slow things down. So I would recommend trying Java and see if it is fast enough.

In some cases it might be beneficial to use a fast fourier transform first and apply the filtering in the frequency domain but I doubt that this is faster than about 6 multiplies and a few additions per sample for a simple lowpass filter.