Patent ID: 8457301

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