Keithley 4200A-SCS

Section
6: Clarius Model 4200A-SCS Parameter Analyzer
Reference Manual
6-254 4200A-901-01 Rev. C / February 2017
LOGFIT Formulator function
Performs a base-10 log-linear fit.
Usage
LOGFIT(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 = LOGFITA + LOGFITB * log(X)
where LOGFITA and LOGFITB are fit constants.
• Using the above logarithmic relationship, returns a new column (vector) containing Y values
calculated from all X values in column VX.
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
GOODFIT = LOGFIT(GATEV, DRAINI, 30, 50)
Also see
LOGFITA (on page 6-255)
LOGFITB (on page 6-256)