Noice level of 2206B MSO

Can you verify if the noice level I'm experiencing is correct for the 2206 please. The data sheet says <200uV RMS, but I'm seeing 1.8mV RMS, 11.85mV P-P. This is powered from a Mac laptop (Windows version of software) and is the same with or without power. Results are the same if I have both probes connected to their ground clips or no probes fitted.

Hi,

The noise level from the PicoScope 2206B data sheet says that the noise is

< 220 μV RMS (±20 mV range)

From your capture it looks as if you are on the ±200 mV range and have zoomed in vertically. As you use higher voltage ranges the noise will increase to move than the 220uV RMS figure but will be the same or smaller as a % of the total range.

The PicoScope 2206B is an 8 bit device which means there are 256 vertical steps. A single bit of noise will be 0.16mV. On the 200mV range one bit of noise will be 1.6mV and on the 20V range it will be 160mV. This is normal behavior on all scopes - the noise level as a figure in mV goes up as you go up through the voltage ranges but usually as a percentage of the total range it will be around the same or a bit less.

I dont have a 2206B with me so hopefully someone will run a test next week just to confirm what you are seeing is normal but I am fairly sure all is OK and you are seeing a lot of noise due to zooming in.

Regards
Alan

Thanks for the response. I investigated further. It requires the probe to be in 1x mode, as in 10x mode I only get +-200mV, while in 1x mode I get +-20mV and indeed the noise level is 195uV. Thanks.

I believe 1x mode has a big impact on bandwidth, what's the 1x bandwidth with the standard probes?

Just found the 1x bandwidth of the 60MHz probe in the specifications - 15MHz.