Noise pattern

[kzeprf22]

HI has anyone recoginze the noise pattern shown in the attached image? Is 100 Hz (arount 10 mV in output) as shown in oscilloscope and is superimposed in practical any voltage trace of my amp. In power suply and in input - output. Because i control the amp using micro, is there a possibility that this pattern comes from a faulty misbehaving crystal-resonator?

[DUG]

As soon as I saw the 100Hz reference I said to myself...This person must be living in an area that uses 50Hz as a power frequency.


If this appears everywhere then the possibility exists that there is a ground loop with the hookup for your measurement or that the "ground" connection for your scope probe is not connected to a good ground reference.

"faulty misbehaving crystal-resonator"...probably not.

One has to be careful in setting up a noise measurement...the setup itself can show signals that are not really there.