Patent attributes
A method for generating a control signal from an inaudible acoustic signal comprising modulating the inaudible acoustic signal, wherein the inaudible signal is converted to a modulated inaudible acoustic signal comprising a first frequency comprising 17 kHz over a time duration of 50 ms, a first null over a time duration of 50 ms, a second frequency comprising 18 kHz over a time duration of 100 ms followed by a second null over a time duration of 50 ms, transmitting the modulated inaudible acoustic signal and an audio signal to a signal receiving device, sampling the modulated inaudible acoustic signal at a frequency of 16 kHz, wherein the modulated inaudible acoustic signal is converted to a digitally modulated inaudible acoustic signal, filtering the digitally modulated inaudible acoustic signal to provide an acoustic filter response signal comprising an acoustic null component and an acoustic down-converted component, demodulating the acoustic filter response signal, wherein the acoustic down-converted component is isolated from the acoustic null component, the isolated acoustic down-converted component representing a control signal.
