Martyn wrote:What is the purpose of these calculations ? What are you trying to determine from the data ?

Purpose is functional testing of the scope. Reversing the operation is very good for that. Before processing real data and drawing (sometimes very important) conclusions these kinds of tests are essential. I have stuck with Pico because do not know any other scope that can support page wide formulas in real time without time-consuming use of external software.

Specific test was requested from me by scientist to see if Pico performs better than scope from other company (that he is currently using) with differentials/integrals. It would, if not described bugs.

Picture of similar bug attached. Problem is not the sample points count. Probably error lies in incorrect internal boundary condition handling at the start of the trace.

Bug 1:

integral(A[0.0001]) works (integral on time advanced channel)

integral(A[-0.0001]) does not work (integral on time delayed channel)

Bug 2:

Time skew does not work in complex formula,

will display "Invalid formula".

Example: A-B phase calculation:

acos(integral(A[0.0001]*B)/(sqrt(integral(A[0.0001]*A[0.0001]))*sqrt(integral(B*B))))/pi*180

Suggestion: Channel time skew compensation is basic feature of DSO. It must work with full complexity math. However it is cumbersome to have it only in math channels. Would be very helpful to also adjust global time skew for channel in channel menu (where probe X is set etc) and in math independently. VHF freq range is problematic with multiple channels and BNC cables w/o time skew compensation (non-equal length cables may be a problem etc).