CT input noise

Hi guys,

I'm experimenting using your eMonTX code on a standard Arduino board connected to an CT sensor from ITeadStudio (via the required external components)

One thing I have noticed is that there is a lot of input noise (about 15mV peak to peak), which in my case this equates to about 30 - 50W of noise.

I have tried to keep the wires to the bias voltage circuit as short as possible, but it doesn't seem to make much difference. The noise looks to be approximately 1.5Mhz, so is probably created by the Arduino its self.

I've tried to damp it out with some smaller value caps, but I've not had much success.

Can anyone tell me what size of noise should me on the bias voltage for a CT input ?