Specifications

Chapter 4 97
Preparation for Accurate Measurement
Fixture Compensation
4. Preparation for Accurate Measurement
Example program for execution of fixture compensation
After connecting a text fixture, the program shown below enables the fixture compensation
function of the fixture compensation kit. In this program, after defining the standard values
for the Open/Short state of the fixture compensation kit by using values prepared by the
user, the fixture compensation function is enabled by measuring each standard. In addition,
when the fixture compensation function is enabled, the internally calculated fixture
compensation coefficient is saved in the external controller.
Example program using HTBasic
The program shown in Example 4-5 is saved under the filename com_meas.htb on the
programs disk. The details of this program are explained as follows.
Line 80 Sets the GPIB address.
Lines 120 - 130 Substitutes a variable for the type of text fixture and the obtained
fixture compensation data point.
Lines 150 - 160 Sets the type of text fixture and the obtained fixture compensation data
point.
Lines 200 - 230 When a custom test fixture is selected, defines the electrical length of
the test fixture.
Lines 250 - 270 Asks whether to define the standard values for the fixture
compensation kit with the values prepared by the user.
Line 280 When each standard value is defined with a value prepared by the user,
the program branches to define each standard value for the fixture
compensation kit.
Line 300 Without using the list-setting function of the fixture compensation kit,
selects a setting that defines each standard value at a common unique
value over all frequencies.
Lines 340 - 440 Defines the values of Open (G-C) and Short (R-L). However, each
standard value is defined in the sub-program (Inp_data).
Lines 490 - 550 Measures the fixture compensation data for the Open/Short state
standard. However, measurement of the fixture compensation data is
performed in the function sub-program (FNFixt_comp). Despite
whether there is any GPIB error during measurement of the fixture
compensation data that comes back as a return value of the function
sub-program, when an error is detected, the execution of the fixture
compensation is halted at that point.
Lines 590 - 630 Calculates the fixture compensation coefficient and turns on the
fixture compensation function. After that, displays completion of
execution of the fixture compensation.
Lines 670 - 690 Reads the number of points in a sweep and, using those values, resets
the range of array variables used when the fixture compensation
coefficient is read.
Lines 710 - 750 Reads the two arrays of fixture compensation coefficients in ASCII
transfer format.
Lines 770 - 840 Saves the read arrays of the fixture compensation coefficient in binary
format in the external computer. After that, displays completion of