I'm wanting to use the FFT256 (or FFT1024) code to display the spectrum of a waveform which has been sampled by the Teensy audio board. Am I correct in thinking that FFT256 only accepts data from a mono signal? I believe this to be the case as the data seems to be arranged, before calling the CMSIS FFT routine , in the form (real = data sample, imag = 0), (real = next data sample, 0) etc. The resulting anambiguous spectrum which can be displayed is then only 22kHz (for a sampling frequency of 44kHz).

It would be good if there could be made available a stereo version of FFT256 in which the data is arranged in the form (real = I data sample, imag = Q data sample), (real = next I data sample, imag = next Q data sample). This would then enable the full unambiguous 44KHz of spectrum to be displayed - just right for a software defined radio!