Question
I do not completely understand the delta time accuracy calculation for my oscilloscope.
In the formula "Fs" is mentioned. This sound like Full Sclae to me. I do not really understand the calculation.
Can you give me an example how to perform it?
Answer
The following informations can be found in the specification sheet of the scope (here RTM3000):
With "Fs" we do not mean "Full Scale" - it is the variable value standing for the Sample Rate in Sa/s.
Let's assume a requested sample rate of 1,09E8 Sa/s and a time delta measurement value of 50 µs and perform a sample calculation @ a time base accuracy of 3.5 ppm:
1,34/1,09*10E8 Sa/s + 3,5 ppm * 50 µs
= 1,229 * 10E-8 s + 3,5E-6 * 50E-6 s
= 1,229 * 10E-8 s + 1,75E-10 s= 1,247 * 10E-8 s
= 12,47 ns
