Microcontroller Based STFT-Vibration Analyzer

The microcontroller based STFT-vibration analyzer (STFT-VA) performs iteratively the short-time Fourier transform (STFT) on a windowed non-stationary signal, resulting in a more accurately spectrum achievement. Actually, the signal is windowed in relation to the lowest frequency value of a range, and the STFT is applied on the signal segments obtained by iteratively decreasing a number of samples from that window. Resulted spectrum is accomplished by identifying the biggest amplitude of each frequency bin. The period of frequency scanning is inversely related to the lowest frequency value and the spectrum refresh rate as well. High-resolution ADC and high-frequency processing microcontroller's features help to achieve an almost continuous spectrum. The device can be useful in many vibration based implementations, and its most significant advantages are the easy operation, small dimension and low-cost.