We just get started with the PS2407B with a laptop. We noticed that when more than one channel are switched on in the PicoScope software, some noise is induced on the scope.
PS2407B was connected with a laptop(later also checked with PC and same behavior).
A 1kHz pulse signal with 2V Max voltage was sent to channel C. The statistic of Max value shows sigma of ~10mV.
As channel D was switched in the software, the sigma raised to ~60mV, whenever the physical port was open, connected with a 50ohm resistor, or any other input.
The screenshot and data file of both cases are attached.
Would you please identify how does this noise come from and how can we prevent it?
Thank you very much.
I am not sure that this is noise, but is instead linked to the difference in sampling rate between the two captures and the application of Sin(x)/x Interpolation.
If you right click on the display and select "View Properties" you will see that you have 1nsec sampling interval for one active channel and 2nsec interval for two active channels. If the value beside the "No. samples" has an additional number in brackets this means that interpolation is being applied to fill in the gaps between samples. I would suggest going to Tools->Preferences->Sampling and turn this off to see what the raw data is like. You will then see the individual samples around the peak you have and how this differs between each buffer that is collected.
Hello,
Thanks for the reply. We checked as you suggested but I don't see different behavior.
If I look at the property when switching on more channel, the no. samples decrease as more channels are activated. Statistics also get worse with more channels, reached the largest number with two idle channels(A:signal;B,C:activated but not connected).
Best regards,
Minjie
I am not sure that this is noise, but is instead linked to the difference in sampling rate between the two captures and the application of Sin(x)/x Interpolation.
If you right click on the display and select "View Properties" you will see that you have 1nsec sampling interval for one active channel and 2nsec interval for two active channels. If the value beside the "No. samples" has an additional number in brackets this means that interpolation is being applied to fill in the gaps between samples. I would suggest going to Tools->Preferences->Sampling and turn this off to see what the raw data is like. You will then see the individual samples around the peak you have and how this differs between each buffer that is collected.
When you add in more channels, the sampling rate drops, so with your narrow pulse you can't always guarantee to take a sample at the highest part of the pulse. Therefore any peak measurements you take will be compromised.