Keithley 4200A-SCS, Reference Manual

Page: 525 / 1381

Section 6: Clarius Model 4200A-SCS Parameter Analyzer Reference Manual
6-256 4200A-901-01 Rev. C / February 2017
LOGFITB Formulator function
Performs a base-10 log-linear fit.
Usage
LOGFITA( VX , VY , STARTPOS , ENDPOS )
VX The name of any column (vector) listed under Columns
VY The name of any column (vector) listed under Columns
STARTPOS
For the range of
X
and
Y
values to be logarithmically fitted, the row number (index)
of the starting values
ENDPOS
For the range of
X
and
Y
values to be logarithmically fitted, the row number (index)
of the ending values
Details
Performs a base-10 log-linear fit as follows:
•
Fits the following logarithmic relationship to a specified range of values in two columns (vectors)
(one column,
VX
, containing
X
values and the other column,
VY
, containing
Y
values):
Y = L LOGFITB * log(X)
where
LOGFITA
and
LOGFITB
are fit constants.
•
Using the above logarithmic relationship, returns the value of the constant
LOGFITB
.
If a
VX
or
VY
value at either
STARTPOS
or
ENDPOS
is an invalid number (that is, the value is
#REF
),
the function will not return a valid result.
Example
FACTOR = LOGFITB(GATEV, DRAINI, 30, 50)
Also see
LOGFIT (on page 6-254)
LOGFITA (on page 6-255)