Day: December 28, 2014

The green trace is the audio signal waveform, and the red trace is the FFTed version. If you change the CW pitch or the tuning, the peak position moves accordingly.

So this could be a CW tuning indicator in its primitive form.

% gcc -Wall -std=c99 test53.c -o test53 -lm -lasound -lfftw3 `pkg-config --cflags --libs gtk+-2.0`

The library FFTW is used here.

Now we combine two programs, namely: IC-7410 Rig Control Program using gtk+ and IC-7410 Audio I/F program using ALSA.

The ALSA part is responsible for capturing the audio signal from IC-7410 and writing the data to stdout, which is pipelined to an audio player program, aplay.

Or you can display the waveform on the screen.