Independent hysteresis apparatus for tone detection

Information signal detection device and information signal detec

Low power signal detection

Low-frequency alternating current signal detector, in particular

LPC-based DTMF receiver for secondary signalling

Machine answer detection

Method and apparatus for analyzing dual tone multi-frequency...

Method and apparatus for converting frequency signals representi

Method and apparatus for decoding DTMF tones

Method and apparatus for detecting an activation tone

Method and apparatus for detecting control signals

Method and apparatus for detecting dual tone alerting signal...

Method and apparatus for detecting reception of a tone signal

Method and apparatus for detection of a telephone CPE...

Method and apparatus for DTMF detection

Method and apparatus for DTMF detection and voice mixing in...

Method and apparatus for electronically detecting speech and ton

Method and apparatus for performing high-density DTMF,...

Method and apparatus for performing spectral processing in...

Method and apparatus for periodic signal detection