jamming or canceling annoying tx of sound
for example resend the same signal inverted!
any idea?
I don't think there is a way to cancel that annoying sound with your method, I mean, resending a mechanical wave (sound) that interferes destructively with the other signal coming out from the speaker, wich is time,phase and surely frequency varying.
The "easiest" way to isolate sound is using an anechoic chamber or using absorbent/reflectant materials.
I would be inclined to look for the source of the sound. Maybe you could filter it.
Another possibility is that it is caused by interference. Try re-routing the speaker wire. Turn off near-by electronics (one at a time) and see if that helps.
If it's a sinewave it might be some parasitic oscillation in your amplifier. If it's noisy check your power amplifier it might need replacement. If it's crosstalk rerout the wires as said before.
If the signal is coming from the speakers of your neighbors, the easiest way to cancel it is to give them a call to turn the volume down.
thanks for the concern. The sound is from a place kms away from me. A person talks things in the morning.
Knowing thqt the apparent source is Km's away is very useful information.
Is your system a radio receiver or is it some sort of player like a CD audio system? Look for possible signal paths and see what you might do to block the interference (without blocking the desired signal). Filters? Re-arrange antennas? "Better" grounding? Don't listen in the morning. etc.
Clayton Paul has a book on the subject if interference control that may be helpful
I think that what he's trying to do is jamming his neighbor's loud speaker transmission.
By "definition"...
"Radio (and Radar) jamming. This is the most fun and most dangerous job in tactical EW. Jamming radio involves transmitting lots of power in the same frequency to overwhelm the radios of the parties involved."
So, if you transmit lots of power in audio frequency range, you'll be generating another annoying sound.
In conclusion...
Just cut your neighbor's power off
They have put large speakers and the new thing is they have added echo. The sing in an annoying way. its not a cd just a microphone and his voice.
I wish I have the ability to turn power off.
About the jamming is it affordable to transmit that power?
what if take the signal do phase shift and send it back?
thanks
If you could exactly match the amplitude and cancel the phase, then it would vector null out the sound. Unfortunately, that is not an easy thing to do. If you move 1 meter away, the amplitude and phase of the needed nulling signal would have to be changed to different settings. The echo, being a slow phenomenon, would not effect the null depth at all. If there were a wide frequency range inthe content, like music, it would be hard to get the right cancellation throughout the frequency range.
One way to solve the spatial problem is to confine the distance. Bose makes some headphones where, since they are mounted on your head, they just have to worry about the difference in space between the outside and inside of the headphones, and they can get a good nulling depth over a wide frequency range.
The only other thing is to add white noise, or sound of your own, nearby to drown out the signal.
do you have a circuit?
can a simple adder be used? amplifier with rc?
You need to VECTOR cancel the signals. No a simple adder will not do that. You need to match the two amplitudes, and match the two phases with one being 180 degrees offset. You have to do this across the entire frequency band of the annoying signal.
Cancellation of noise is technically used in some applications, it works practicable for low frequencies. If I remember right, it has been used with jet pilot's earphones. At low frequencies, the interferring sound can be treated as scalar sound pressure within a volume of interest. But as biff44 mentioned, sound in general is a vectorial signal, you would need multiple measuring microphones and multiple speakers to compensate an interference for a region, e. g. a room. If you have a far source, the sound appears effectively as a parallel wave at the destination. This may ease the compensation somewhat, but a complex signal processor would be used anyway.
Thanks to all.
Yes the sound is fro a far place. it is a sound of a monotone singer with no music