2 ms·
> when transmitting ultrasounds through air: at 2m, to > produce 5W at the receiver, you need to generate 25W at > the transmitter Where does that 2m come
by harryh 10y ago
> when transmitting ultrasounds through air: at 2m, to
> produce 5W at the receiver, you need to generate 25W at
> the transmitter
Where does that 2m come from? It has to do with the frequency of the sound right? I don't remember enough physics. :(
- Renaud 10y ago2m is what they demoed if I'm right. The power attenuation actually varies a lot and is dependent on ultrasound frequency, temperature, humidity, air pressure... You get better transmission at low frequencies, but below 100kHz you risk affecting pets. Some details and a link to an interesting paper: http://physics.stackexchange.com/questions/52195/ultrasonic-wave-through-air http://physics.stackexchange.com/questions/52195/ultrasonic-...
- harryh 10y agoYa, it's the power attenuation calculations that I'm trying to relearn/reremember how to do. I'll keep futzing around. Is fun. Thx for the link.