The Audio Syntiant processing block extracts time and frequency features from a signal. It is similar to the Audio MFE but performs additional processing specific to the Syntiant NDP101/120 chip. This block can be used only with Syntiant targets.

Syntiant spectrogram of the sentence \'Hello, World\'

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Audio Syntiant parameters

Log Mel-filterbank energy features
  • Frame length: The length of each frame in seconds
  • Frame stride: The step between successive frame in seconds
  • Filter number (fixed): The number of triangular filters applied to the spectrogram
  • FFT length (fixed): The FFT size
  • Low frequency (fixed): Lowest band edge of Mel-scale filterbanks
  • High frequency (fixed): Highest band edge of Mel-scale filterbanks
Preemphasis
  • Coefficient: Pre-emphasis coefficient
Chip
  • Features extractor: Syntiant method to generate features, choose accordingly to your chip

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How does the Syntiant block work?

The features’ extractions is a proprietary algorithm from Syntiant. However parameters are very close to the Audio MFE. Pre-emphasis coefficient is applied first to amplify higher frequencies. The signal is then divided in overlapping frames, defined by the Frame length and Frame stride to extract speech features.

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Sampling frequency

The Audio Syntiant block only supports a 16 kHz frequency. You can adjust the sampling frequency in the “Create Impulse” section.