Research Article

Short-Time Fourier Transform and Decision Tree-Based Pattern Recognition for Gas Identification Using Temperature Modulated Microhotplate Gas Sensors

Figure 4

The STFT amplitude spectrums of sensor responses to three analytes modulated with the rectangular modulation waveform at 4 s period. Hann window is used as the window function. The length of the window function is 375. (a) 150 ppm carbon monoxide; (b) 3000 ppm methane; (c) 50 ppm ethanol.
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(b)
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