[VB6] - Signal spectrum

[The trick]

Hello everyone!
This project contains the sound signals generator with the spectrum visualizer. The list of signals contains the following forms:

1. White noise;
2. Pink noise;
3. Brown/Red noise;
4. Blue noise;
5. Violet noise;
6. Sine modulation by low frequency;
7. Square wave (odd harmonics with 6db/oct attenuation);
8. Saw wave (odd/even harmonics with 6db/oct attenuation);
9. Triangle wave (odd harmonics with 12db/oct attenuation);
10. Signal with only even harmonics;
11. Complex FM modulation;
12. AM modulation.

The spectrum visualizer supports resolutions up to 32768 points and averaging. The discrete complex FFT (Fast Fourier Transform) is used to visualize the spectrum. This procedure is optimized to processing a real signal using the even/odd decomposition in frequency domain which allows to performs the transformation of 2 real signals as single complex signal. The further synthesis of the spectrum is based on shifting in time domain and corresponding frequency domain rotation. The comments in the code describes everything in details.



Best Regards,
The trick.