Axtell's Notes: June 8

Today I built a class that could compute the FFT and show the graph of any WAVE file it was given. It includes a simple menu with a few different options.

I checked the graphs it was making against the graphs Sonogram made for the same WAVE files to ensure that the FFT algorithm works properly.

Once it was written, the rest of the day went to debugging it. The plain FFT works and automatically scales it so it is nicely visible. The windowing and comparison options do not work as they should (instead of a smoother FFT it displays a straight line), so that's on my to do list for tomorrow.

I also need to add numbers to the x-axis saying what frequency is where. I was starting work on finding the frequencies today and hopefully will have that working tomorrow.

I did find out that my FFT method is doing something odd. I only use half the number the method makes because it mirrors itself. Ignoring the second half of the numbers should fix that, but I found out that I was too far zoomed in. If I zoomed out I could see that my function still mirrored itself. I was not able to find out how that was happening, but if I used only a 100th of the list or so, I got rid of the mirroring.

So I have the start of a useful program that is still full of bugs. Tomorrow I hope to work out most of the bugs and do some more research into what should be added to the program next.