I have this scope with the following real-time sampling rate and memory depth:
I know the relation between the memory depth, sampling rate and time duration as:
LM = SR x TD
Where LM is the long memory depth, SR is the sampling rate and TD is the total time on the scope screen(time per division x total number of horizontal divisions).
I also know/learned that the scope adjusts its sampling rate when we change the times per division setting.
So I first set the memory depth of the scope as LongMem which is given as 2Mpts:
Then I set the times per division as 1ms.
This means that the total duration for the plot is 18x1ms = 18ms. It is because in this scope the total number of horizontal divisons is 18.
So from the equation I should get the follwing sampling rate:
SR = LM/TD
SR = 2 x 10^6 / (18 x 10^-3 sec)
SR = 111MSa
But here is what the scope shows as its sampling rate which is 25MSa:
What can be the reason I am getting different result for the sampling rate?