use microphone to receive an inaudible tone?
<p>I am doing a project. I want to use the speaker of computer to generate an inaudible tone and microphone on smartphone to receive this tone. </p>

<p>1.what software that can generate the inaudible tone (18- 20 Khz) through the speaker in PC ?</p>

<p>2.A code android to receive and analyse some features (frequency, amplitude,…) of this tone?</p>
