SBAA600 October   2024 TAA5212 , TAC5111 , TAC5112 , TAC5211 , TAC5212

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Voice Activity Detection
    1. 2.1 VAD Configurations
      1. 2.1.1 User, Auto, Intermediate
      2. 2.1.2 VAD With ADC Recording
      3. 2.1.3 VAD Monitoring Channel
      4. 2.1.4 VAD Interrupt Pin
      5. 2.1.5 MICBIAS Enable During PDM Monitoring
      6. 2.1.6 VAD Clock Configurabilty
    2. 2.2 VAD Parameters
      1. 2.2.1 Initial Learning Period
      2. 2.2.2 Hold Over Counter
      3. 2.2.3 Wakeup Wait
      4. 2.2.4 Threshold
  6. 3VAD Performance Results
  7. 4Examples
  8. 5Summary
  9. 6References

2.2 VAD Parameters

Table 2-10 shows the parameters of the VAD algorithm. These parameters reside in the 32-bit wide coefficient memory (Page 0x0D, 0x0E) of the device.

Table 2-10 List of VAD Parameters
VAD Parameter Function, Description
Initial learning period (ILP) This is the amount of time the VAD algorithm takes to adjust to the background noise environment, from the time instant VAD is turned on.
Hold over counter (HOC)

The HOC determines how long the VAD interrupt can stay active after voice activity is determined to have ended. This can be lowered so that the interrupt reacts to the space in between words, or increased to mak sure the recording of an entire sentence.
Wakeup wait (WW) If VAD is programmed to be in Auto mode, on detecting voice, VAD automatically turns on the ADC and starts recording, simultaneously also checking for voice activity. Wakeup wait is the amount of time for which VAD is suspended after going to recording mode and thereafter resumed.
Threshold (TH) Threshold controls the decision boundary of the nodes of the decision tree. A higher value can increase the node thresholds of all the nodes of the decision tree, thus reducing the likelihood of false positives. Similarly, a lower value for the threshold parameter decreases the node thresholds, which reduces the likelihood of false negatives.