| 摘要 |
A baby cry recognizer is disclosed which includes an amplifier circuit for amplifying a received sound signal. In response to the amplified sound signal, a pulse generator circuit generates a pulse signal having zero crossings which are aligned with zero crossings of the amplified sound signal. The pulse signal, in turn, is inputted to a signal recognition circuit. The signal recognition circuit is capable of obtaining the zero crossing rate of the pulse signal during each of a preselected number of frames in a predetermined length time interval. The signal recognition circuit then determines if the zero crossing rate of the pulse signal, in more than a first threshold number of this preselected number of frames, is within a particular frequency range. The signal recognition circuit also determines if the zero crossing rate of the pulse signal over the entire time interval is greater than or equal to a second low threshold but less than or equal to a third high threshold. If these two conditions are satisfied, then the signal recognition circuit outputs a signal indicating that a baby's cry was detected.
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