Invention Grant
US08457301B2 Multi-frequency tone detector 有权
多频音检测器

Multi-frequency tone detector
Abstract:
A tone detector for detecting a tone having a plurality of targeted frequencies comprises a first filter bank providing frequency estimates for an initial indication of a presence of each of the targeted frequencies; a second filter bank being controlled by the frequency estimates and comprising a plurality of filters operating in different frequency bands, each frequency band comprising at least one of the targeted frequencies, each of the filters providing a modified signal; a third filter bank extracting a noise signal from the input signal; a plurality of level control units (LCU) providing normalized modified signals having a constant amplitude; a power estimation module providing a power estimation parameter for each of the modified signals and the noise signal; and a discrimination module controlling a plurality of demodulator modules, each of the demodulator units providing a fine estimate of one of the targeted frequencies.
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