VVM (Vector Voltmeter) Mode - Option 308
171
How to select Zeroing
Press
Meas Setup 4
Then
Zero
Press
Zero OFF
to turn zeroing off.
1-Port Cable Trimming Measurements
A 1-Port Cable Trimming measurement is used in a cable fabrication procedure
to validate proper electrical length.
FieldFox Block Diagram
The
R
receiver measures incident signal (green
line) out of the source.
The
A
receiver measures reflected signal (red line)
from the end of the DUT (black line).
In VVM mode, the display ALWAYS shows ratioed
(A/R) measurements which is the electrical length
of the DUT.
How to make a 1-Port Cable Trimming Measurement
1. Press
Mode
then
VVM
then
1-Port Cable Trimming
.
2. Press
Freq/Dist
then enter the frequency for the measurement.
3. To improve measurement stability, change the IF Bandwidth, Output Power,
and Averaging settings as needed.
4. Press
Meas Setup 4
then
Zero OFF
.
5. Optionally calibrate the FieldFox. Learn more about VVM calibration on page
6. To ensure that the calibration is adequate, perform the following
optional
Measurement Verification
procedure.
NOTE
This measurement verification procedure is suitable for low frequency
measurements. However, for high frequency measurements, a more sophisticated
procedure is required.
a.
Connect a short standard to
PORT 1
where cables to be trimmed
will be connected.
b.
Press
Meas Setup 4
and press
Zero
.
c.
Remove the short standard and connect the open standard.
d.
Confirm that magnitude measurement is less than –0.1 dB and that
the phase value reads 180° degrees.
7. Attach the shortest cable to the FieldFox
PORT 1
connector. This cable is the
reference cable. Leave the end of the reference cable open (unterminated).
8. Press
Meas Setup 4
then press
Zero
.
9. Remove the reference cable from the FieldFox
PORT 1
connector.