Keithley 2182, User Manual, Page: 322 / 339

I-6 Delta, Pulse Delta, and Differential Conductance
Delta measurement process
The Delta process is shown in Figure I-3 . As shown, three Model 2182/2182A A/D
conversions are performed to yield a single Delta reading. When Delta starts, three Model
2182/2182A A/Ds (A, B, and C) are performed and the Delta reading is calculated. After
the 1st Delta cycle, the moving-average technique is then used. As shown, a Delta reading
is yielded for every subsequent Model 2182/2182A A/D. The new A/D replaces the oldest
A/D in the Delta calculation.
Figure I-3
Delta measurement technique
DELTA
Reading
1st
622x
I-Source0
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