Noise generator humming.

[ericgibbs]

hi hero,

This free download is a great program for audio work, also has a built in noise gen.

Audacity: Download

 

[Mikebits]

Hero, I too suffer from tinnitus, it keeps me awake some nights as it seems so loud at times. It has been constant for several months and has been driving me insane. I went to an audiologist with no answers from the testing.

Lately I have been experiencing numbness in my hand and one of my legs. I am now scheduled for a MRI to see if I have neurological disorder. From what I have been told, ringing in the ears is often an indicator of a underlying disorder. It is best to nag your doctor to check into it. I will update when I know more.

 

[marcbarker]

There's a similar condition to this people have and that's "Humming" getting worse. It drives some people crazy!!. People with start off thinking someone has stopped outside their house with car engine running, then they think it's a power station or some factory noise pullution, they switch off all the power in their house, buy magnetic feild detectors and that they use to 'clean' their house from top to bottom of demonic magnetic feilds. They complain to the council's noise control department, who 'don't take any notice', then I heard of one guy who moved out of london into the country to get away from it, and the 'humming' followed him there, I don't know what happened to him. People take this thing really seriously, there is hum clubs around the world who have annual 'hum conventions', I am not making this up!!!

Anyway, there's a growing body of belief now (well in 2006 that was) that the humming sound is actually "caused by the person hearing it", the cause and effect of the humming are entwined somehow, the best theory is recent research (as far as I know) discovered that ear system has a muscle that operates automatically, and that something to do with a vibration in the control system, some kind of feedback loop like a microphone and speaker. Well anyway how I know all this is my ex-gf had it, I cured her before it took hold, with FM radio, then a pink noise CD, with a volume turned down as the weeks went on, her side of the bed. Biggest problem I think is the psychologic one, it's convincing the person who thinks they have it, that it's not something outside their body that's doing it, it's that they are hearing themselves hearing it.

 

[Mr RB]

I agree with a lot of that marc, especially with tinnitus if you keep looking for it (listening?) it becomes part of your habit system and you burn in the neural pathways in your brain to be better at detecting that low level noise (and be constantly aware of it) from your auditory nerves that is always there with everybody. It's like tuning the radio to a part of the band where there is a little noise then turning the treble right up.

Not trying to trivialise tinitus for anyone who suffers from it but I think those treatment options that include retraining are worth looking into.

And I think there would be a good market out there for electrical device that helps you retrain the brain, but not pink noise I would make it pulse different frequencies randomly ie different frequencies, volume levels and periods of silence. It would retrain the brain to focus the neurons on picking up actual noise in unexpected patterns not the continuous fixed freq focus.

 

[Hero999]

Thanks for all the support everyone.

Yes, I've got a pink noise cassette, I just want to have something that doesn't need any CDs or tapes to mess around with, plus I've not built anything for awhile.

It will also have a white noise option which might prove more useful to me as my tinnitus is quite high pitched.

 

[Ghosty_Ghoul]

[latex]Vn_{(RMS)}=sqrt{0.007 \times 20000^2}= 11kV[/latex], no that can't be right!

Yes, you've got it totally wrong!

I'll give you a clue, with pink noise the power over each octave is the same, the power over the next octave is double the previous. Example with white 100Hz to 200Hz will be 1W, 200Hz to 400Hz will be 2W and with pink there will be 1W over both 100Hz to 200Hz and 200Hz to 400Hz.

Get it?

I hope I've given you an idea.

 

[Hero999]

Hi Ghosty welcome to the forum.

That's helpful but the maths are still confusing, I'll think about it more and I'm sure I'll figure it out.

 

[R@H]

I'm building this noise generator to drown out my tinnitus but according to the scope waveform it appears to be picking up hum.

I know the TL082 doesn't have enough open loop gain at the middle of the audio bandwidth for a gain of 1001 but this is just a proof of concept circuit at the moment.

I assume, it's picking up hum because I built it on a breadboard and the long leads are picking up the mains. The interesting thing is it's only picking up the negative cycle at half the mains frequency. The power supply is my bipolar power supply which seems to be alright hum-wise.

Attached is the schematic and the waveform. The top waveform is the output from the noise generator and the bottom is the waveform generated when I hold the oscilloscope's probe and pick up hum.

I will build this on a propper PCB but before then, I want to ensure it works properly. Is there anything I might be doing wrong?

what is the programme you used to simulate this circuit?
i used multisim but the result Not identical with your figure

 

[picbits]

Hero999 no longer comes on this forum and this thread is around 4 years old.

 

[R@H]

Ok
i know is around 4 years old.
But what is stopping you can find one benefit me

 

[picbits]

You asked Hero999 a question. He left the forum a couple of years ago - I'm letting you know that he probably won't be around to answer your question.

 

[R@H]

OK
can you help me in my circui

 

[picbits]

OK
can you help me in my circui

What circuit ?

 

[picbits]

Looking through the above thread, I see no simulations. Any pictures Hero999 posted up were real photographs of his oscilliscope trace. You will often find that a circuit built on a breadboard or PCB performs very differently to a simulator. The capacitance of the board along with other external factors such as mains hum and RF interference also affect the performance of a circuit.

 

[R@H]

mobile jammer
but now i want to understand the IF section Specifically (noise generation circuit)

 

[picbits]

You'd be better off starting a new thread of your own and asking on there.

Be warned that moble jammers are illegal in many countries as it prevents people making emergency calls and interferes with other equipment.

 

[R@H]

ok
Thanks alot

 

[audioguru]

I guess you are using a zener diode to make low level white noise. Maybe that is why you want a voltage gain of 1001.
The TL082 is a dual opamp so each one can have a gain of 31 for a total gain of 961 and the total bandwidth goes to 50kHz.

Of course the connecting strips and wire on a breadboard pickup mains hum. A breadboard should be used only for low impedance, low current, low frequency circuits or DC.