Keithley 6220

5-22 Delta, Pulse Delta, and Differential Conductance Model 6220/6221 Reference Manual
Return to Section 5 topics
Figure 5-7
Delta measurement technique
The following equation can be used to calculate any Delta reading:
Where: X, Y and Z are the three A/D measurements for a Delta reading.
n = Delta Cycle Number – 1
Example – Calculate the 21st Delta reading:
X, Y, and Z are the three A/D measurements for the 21st Delta reading.
n = Delta Cycle Number – 1
= 21 – 1
= 20
Therefore:
DELTA
Reading
1st
622x
I-Source
0
time
1st Delta Cycle
2nd Delta Cycle
I-High
I-Low
3rd Delta Cycle
4th Delta Cycle
A - 2B + C
DELTA
Reading
2nd
(
1st Delta Reading =
4
)
〈
(-1)
0
B - 2C + D
(
2nd Delta Reading =
4
)
〈
(-1)
1
C - 2D + E
(
3rd Delta Reading =
4
)
〈
(-1)
2
D - 2E + F
(
4th Delta Reading =
4
)
〈
(-1)
3
DELTA
Reading
4th
DELTA
Reading
3rd
2182/
2182A
A/D B
2182/2182A
A/D A
2182/2182A
A/D C
2182/2182A
A/D E
2182/
2182A
A/D D
2182/
2182A
A/D F
Delta
X2Y– Z+
4
---------------------------
⎝⎠
⎛⎞
1–()
n
•=
Delta
X2Y– Z+
4
---------------------------
⎝⎠
⎛⎞
1–()
20
•=
X2Y– Z+
4
---------------------------=
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