I am looking for good implementations of the Fast Hartley Transform for the Teensy 3.0 or 3.1; I have been looking at the Arduino FHT library for example (but this uses embedded asm so is not portable). Can anyone recommend something written ideally in ANSI C for portability please? I would be using signed 16 bit integers for input and output (e.g. the output from an ADC). I could potentially use an FFT instead, however, the performance gains of the FHT make this more attractive and I need a faster implementation than the FFT could perhaps provide.
Thanks.
Thanks.