Math, USB Isolation cable

Math, USB Isolation cable, a forum discussion on Cleverscope Mixed Signal USB Oscilloscopes. Join us for more discussions on Math, USB Isolation cable on our Interface issues forum.

Dimensions

11 Mar 2008
Posts: 27

Is there a way in math after measuring the frequency of a waveform to do math applying it to the horizontal axis? For example (channel A freq*60 and put into B)

After adding an isolation USB cable to my Cleverscope I have noticed that I have a ground path through the AC adapter, which is class I. I am confused, why offer a isolated USB adapter that provides somewhere in the region of 1 to 2Kv of isolation when the AC adapter has a connection from power supply neg (common with the Cleverscope BNC ground) to earth ground?
bartschroder

14 Mar 2008
Posts: 481

You are quite right - the power supply is not isolated, deliberately so. We have had about 3 cleverscopes returned because the user connected a ground clip to mains power, while not having an RCD/GFI in the local power supply. (Not too hard to fix!) The ground path saves the computer and user from being exposed to mains voltages conducted via the ground clip through the USB ground to the PC/User. If you have a an isolated USB cable, we can supply you an isolated power supply, though for some high dV/dt applications (such as looking at a high side gate drive on a switched mode power supply) the interwinding capacitance of the power supply is still significant, and a battery is better.

There is currently no way to modify the time or frequency axis with Maths (other than interleave, which halves the sample period). I guess what you are after is a Maths equation that results in a new intersample time or frequency delta, based on the existing time or frequency delta. I guess a possible use is to display values in RPM, not Hz. Doesn't sound to difficult - we are doing a new Maths module at the moment, with teh goal of allowing better use of teh maths module in the frequency domain, and being able to apply maths over a whole frame. But you know we are often slow!

:-)
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