| 摘要 |
Usually, a Voice Activity Detector (VAD) 100 will deliver an output state indicating speech presence or absence. It is also known to introduce a constant delay period between a change of output states to confirm the presence (S) or absence of speech (NS) to reduce clipping of speech and to avoid falsely detecting speech. However, the constant delay does not produce the best results in all circumstances. The VAD described varies the length of the delay period dependent on the direction of output change (e.g. S to NS or vice versa) and a detected quality of the input signal. For example, if a S to NS transition is detected and the signal is poor, a longer delay period may be used to ensure the speech is not clipped. Conversely, if a S to NS transition with a good input signal quality is detected a shorter delay period can be used which is more efficient. |
