The FIR Filter Designer app designs minimal-order finite impulse response (FIR) digital filters based on performance specifications you provide. The application attempts to find the lowest order (smallest) set of FIR filter coefficients that satisfies the given specifications. The generated filter has approximately unity (0 dB) gain in the passband.

The output of the design procedure is a list of double-precision filter coefficients (Text output option) or an implementation of the filter in C/C++, C#, Java or MATLAB/GNU Octave source code. This output is formatted into an email you can send to any recipients.

Complete source code for the Android FIR Filter Designer app is available at https://www.assembla.com/code/firdesign/subversion/nodes.

Thanks to Jake Janovetz for providing a GPL-licensed implementation of the Parks–McClellan algorithm that served as a starting point for this app.