I am working on an application that will receive ultrasonic waves and it will perform different actions based on the input. At some point, I am going to need that this ultrasonic waves to be unique for my application in the sense that I don't want other waves to interfere.
Can you please give me some guidance on the protocols for making a wave sound "unique"? There are commercials applications for that like cue audio. I am planning to write the application using Android. Thanks in advance.
Asked
Active
Viewed 78 times
0
mate89
- 146
- 6
-
1Incidentally there is a related [stack exchange](https://dsp.stackexchange.com/). – greeble31 Feb 20 '19 at 00:30
-
what frequency range are you thinking of ? normal mic or special input source ? – Scott Stensland Feb 20 '19 at 00:48
-
@ScottStensland around 20 KHz which is apparently close to the limit of a standard microphone. – mate89 Feb 20 '19 at 05:06
2 Answers
2
"Direct sequence spread spectrum" (DSSS) transmission is used to make communication resistant to jamming and interference, which seems to cover your use case as well.
It's reasonably easy to implement digitally. See: https://en.wikipedia.org/wiki/Direct-sequence_spread_spectrum
Matt Timmermans
- 53,709
- 3
- 46
- 87
1
This might be more of a dsp question, but you could use frequency shift keying, where you encode a pattern as a series of frequencies and then recover them: https://www.tutorialspoint.com/digital_communication/digital_communication_frequency_shift_keying.htm
If its for rangefinding, have a look at chirp signals used in radar: http://www.dspguide.com/ch11/6.htm Not exactly what you asked I know but probably of interest as well. These are commonly used in radar systems.
TheMachinist
- 298
- 2
- 10