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Chapter 9 Smith Chart Testing
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Performing calibration
Perform the O-S-L Calibration by pressing the CAL hard key. The instrument displays
on-screen instructions for you to follow through. See "Performing Calibration" on page 33 for
more information.
Making a measurement
Once the O-S-L calibration is done, the instrument is now ready to make a measurement.
Procedure
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501, 1001, and 2001.
NOTE
Default setting is 1001. It is recommended that you select high resolution data points
only for an instance of measuring wide frequency bands or requiring precise
measurement data.
The larger number you choose, the higher resolution you get and the longer the
instrument takes to sweep and display results. For example, selecting 501 data points
provides twice as many measurement points as 251, but it may take twice longer to
sweep and display the trace than choosing 251 data points. Changing data points
does not affect calibration status.
To enable the Interference Rejection feature, select On.
NOTE
Default setting is Off. It is recommended to use this feature only when you suspect
interfering signals in the area as it slows down measurement.
For JD725C and JD726C users with the option 001 Bias Tee installed. To use the Bias Tee,
complete the following steps:
a
Select On for the Bias Tee.
b
Enter a value between 12 and 32 with 1 V step, as you desire.
NOTE
If you have set this Bias Tee to On, the instrument will supply a DC bias of set level
(12 – 32 V) from the RF In port to an active device, such as Tower Mounted Amplifier
(TMA) or Low Noise Amplifier (LNA), through the transmission line, eliminating the
need of an external power supply.
Tap the Apply button in the lower-right corner of the setup screen to save the change(s).
Disconnect the calibration kit from the calibration point.
Connect an antenna or feed line to the calibration point, where is usually at the extension cable
end if used. See Figure 47 for the cable connection diagram.
Your measurement result is displayed on the screen in real time.
CAUTION
Do not apply or connect power exceeding +25 dBm to the RF Out / Reflection port. When
the input signal power is greater than +25 dBm, the input power protection is triggered to
protect the instrument and a measurement comes to stop automatically.
CellAdvisor JD720C User's Manual
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