Figure 6-4 Median Filter (Rank 5) - Keithley 2500 User Manual

Models 2500 and 2502 User's Manual
The number of reading samples (stack size) for the Median Filter is determined by the
selected rank (0 to 5) as follows:
Sample readings = 2n + 1
Where: n is the selected rank (0 to 5)
From the above equation, it can be seen that the minimum number of sample readings is 1
(n=0) and the maximum number is 11 (n=5). The following table shows the number of
sample readings for each rank setting.
Rank
setting
0
1
2
3
4
5
The first-in, first-out stack for the Median Filter operates as a moving type after it fills. For
example, if the Median Filter is configured to sample 11 readings (Rank 5) as shown in
Figure
acquired and placed in its filter stack. Each subsequent reading will then be added to the
stack (oldest reading discarded) and another Median Filter reading will be calculated and
displayed.
NOTE
Figure 6-4
Median filter (rank 5)
Reading #11
#10
#9
#8
•
#7
•
#6
•
#5
#4
#3
#2
Reading #1
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# of Sample
readings
1
3
5
7
9
11
6-4, the first filtered reading will be calculated (and displayed) after 11 readings are
With auto range enabled, a range change cannot occur until a reading is yielded
by the median filter process. Therefore, auto ranging could be very slow when
the median filter is enabled.
If the Repeat Filter is enabled, the Median Filter operation will not start until
after the Repeat Filter operation yields a reading. In other words, after a Repeat
Filter reading is yielded, that reading will then be sent to the Median Filter
stack.
Reading
Median
•
Reading
•
#1
•
Reading
Range, Digits, Speed, and Filters
#12 Reading
#11
#10
Median
#9
Reading
#8
#2
#7
#6
#5
#4
#3
#2 Reading
#13
#12
#11
Median
#10
•
Reading
#9
•
#3
#8
•
#7
#6
#5
#4
#3
6-9