Low level constant Noise/Hash on the output

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chris2u
Posts: 4
Joined: Mon Jul 04, 2016 3:02 pm

Low level constant Noise/Hash on the output

Post by chris2u »

It looks like there is some constant higher frequency hash or pulses on the FG's output..
Here is a pix of a 1KHz/0.1V square wave.

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Same again but with a sine wave.

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With signal level reduced to zero, the noise is still there.

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With the FG turned off but still connected, all is well.

Image

Have tried using a linear power supply and adding caps across C9 and C10. but to no avail.
I hadn't used the FG for a while, so not sure if the problem was always there.
Maybe something needs setting to default?
Any suggestions, Thanks!
jye1
Posts: 1221
Joined: Wed Feb 20, 2013 4:58 pm

Re: Low level constant Noise/Hash on the output

Post by jye1 »

This noise is normal. It came from the digital trimmer U4. We can't find easy way to remove the noises.
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