Schematics > Security and other sensors and detectors > Voice activated switch
Voice activated switch
This circuit uses an MC2830 to form a voice activated switch ( VOX ). A
traditional VOX circuit is unable to distinguish between voice and noise in the
incoming signal. In a noisy environment, the switch is often triggered by noise,
or the activation sensitivity must be turned down. This circuit overcomes this
weakness. The switch is activated by voice level above the noise and not
activated by background noise. This is done by utilizing the differences in
voice and noise waveforms. Voice waveforms generally have a wide range of
variation in amplitude, whereas noise waveforms are more stable. The sensitivity
of the voice activation depends on the value of R6. The voice activation
sensitivity is reduced from 3.0dB to 8.0dB above the noise if R6 changes from
14k to 7.0k .
Title: Voice activated switch
Source: Motorola
Published on: 2005-02-10
Reads: 1014
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