S_TOOLS-STx provides a 2-channel Real Time Analyser to be called either as a stand alone application in MS Windows NT/2000 and additionally in combination with the STx-Recorder in MS Windows XP and Vista/7. The STx RTA offers the following functions:
- FFT-Amplitude Spectrum (STFT), Waterfall display and Spectrogram
- Linear Prediction Coding (LPC) - smoothed spectrum, Waterfall display and Spectrogram
- Cepstrum smoothed spectrum , Waterfall display and Spectrogram
- Display amplitude spectrum minus Cepstrum smoothed spectrum (cp & sp.-cp).
- Display amplitude spectrum channel A and channel A-B
- Linear and BARK frequency scaling
- Selection of FFT-frame length (frequency resolution) and overlap (hopsize) over large ranges
- Linear and Exponential Spectrum Averaging
- Waveform display.
Waterfall Display: Sreenshot of the 2-channel Real Time Frequency Analyser (Frequency axis in BARK).
Fast Fourier Transform (FFT) - Amplitude Spectrum (white) with LPC-smoothed spectrum overlayed (yellow).
Note: the LPC-spectrum represents the all-pole model of unnasalized voiced speech signals. The spectral peaks indicate the resonance frequencies of the vocal tract (formants F1, F2, ...). The order of the model is specified by # of coefficients.
Averaging: the averaging of consecutive amplitude spectra is specified in %.