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Reducing noise of signal using 2206

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Reducing noise of signal using 2206

Postby lauramclister » Wed Jan 09, 2013 3:57 pm

Hi,
I have recently purchased a picoscope 2206 for an outreach science show which is being delivering in primary schools. I am using the picoscope to teach about simple sound waves. However, I realise now that I have bought the picoscope that i really need to reduce the noise that I am getting through my microphone in order to make the produced Sin waves easier to see. After reading the user manual I see that a lowpass filter would have been perfect for this but sadly doesn't come with the 2206.
I have tried creating and adding a reference waveform to my library of the noise and then using the Math channel to subtract this from my incoming signal but when I try and write this it tells me that my formula is not valid.
Does anyone know of any methods of reducing the noise on your signal for the 2206 picoscope?

Thanks
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Re: Reducing noise of signal using 2206

Postby Martyn » Thu Jan 10, 2013 9:33 am

You may be able to use resolution enhancement from the channel setup menu, although that will depend upon the nature of the noise.
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Re: Reducing noise of signal using 2206

Postby bennog » Fri Jan 11, 2013 10:20 am

Are you using a microphone for sound recording or some kind of generator.

edit: I see you use a microphone, what kind of microphone ?

How is all connected to the scope ?

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Re: Reducing noise of signal using 2206

Postby lauramclister » Fri Jan 11, 2013 2:49 pm

Hi,

Thanks for the advice on resolution - I will try that.

Benno: I am using a microphone for the sound recording as we are looking at live sounds (comparing pitch, volume) of a guitar, whistling etc. The microphone is a Shure dynamic mic (c606) mic and at the minute it is connected slightly crudely with a BNC connection, crocodile clips and the end of the mic lead (which is a 1/4" jack). I realise as I write this that that could be casuing a problem with some noise...before we start the show I will be buying proper adaptors for the mic to the oscilliscope but i still think there will be some noise that would be good to reduce.

Thanks
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Re: Reducing noise of signal using 2206

Postby bennog » Fri Jan 11, 2013 4:19 pm

Ok I was afraid you used a condenser microphone. (witch need special circuitry to work properly)

I agree with you that probably 90% (or more) of the noise you see is from the unshielded wires.

So using correct wires (with shielding) and connectors will remove most of the noise.

The output of a dynamic microphone is in the order of 10 – 40 mV so shielding is most important in your situation.

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Re: Reducing noise of signal using 2206

Postby bennog » Sat Jan 12, 2013 6:26 pm

Done some testing over here with a small speaker.
Signal is in order of 1 - 5 mv too little to see any good info on the scope.

I suggest you use a microphone preamp and put the output of this to the picoscope.

Then you will get nice waveforms.

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