Example: Calculating Measurement Error
Calculate the approximate measurement error for a pulse train input
with a crest factor of 3 and a fundamental frequency of 20 kHz.
The internal
DMM is set to the 1 V range. For this example, use the
90-day accuracy specifications of
± (0.05% of reading + 0.04% of range),
as shown in chapter 9 on page 406.
Error
sine
= ±(0.05% + 0.04%) = ±0.09%
Error
crest factor
= 0.15%
Error
bandwidth
=
– 3
2
x 20000
4
x 3.14159 x 1000000
*
100 = 1.4%
Total Error = 0.09% + 0.15% + 1.4% = 1.6%
8
Chapter 8 Tutorial
Measurement Fundamentals
363