www.vtiinstruments.com
EX1200-1538: Introduction
13
A
CCURACY
C
ALCULATIONS
This section explains accuracy calculations for different measurements.
Frequency Accuracy Measurement Using Digital and Analog input
Digital Input
Analog Input
StDev.
Typical % Error
0.0017
0.0019
3
Maximum
%
Error
0.0029
0.0034
6
Period Measurement Using Digital Input
Where:
P
error
= Absolute period measurement error (in s)
F
error
= Absolute frequency error in measurement (in Hz)
F
in
= Input frequency (in Hz)
Period Measurement Using Analog Input
Where:
Pa
error
= Absolute period measurement error using analog inputs (in s)
Pulse Width Measurement Accuracy Using Digital and Analog Inputs
For digital inputs:
Where:
T
P
= Input pulse width (in s)
For analog inputs:
Where :
T
P
= Input pulse width (in s)
Trg
error
= Trigger error (in ns)
