Select The Ecal Options - Agilent Technologies 8753ET User Manual

5. If you need to calibrate with a second ECal module, connect one end of another DB25 cable to the
connector on the PC interface unit labeled "DB25 Interface to ECal Module B". Connect the other end of
the DB25 cable to the parallel cable connector on the ECal module.
NOTE
Why Use a Second ECal Module?
If the frequency span of the measurement that you set up earlier exceeds the span of a
single ECal module, you need to use another ECal module whose frequency range allows the
rest of the measurement span to be calibrated. The frequency range of the ECal modules is
listed in the "General Information" chapter of the 85097A Electronic Calibration System
User's Guide.
6. Using an RF cable (or a microwave cable, as appropriate), connect one port of the ECal module to test
port 1 of the analyzer. Refer to
CAUTION
RF ECal modules can be damaged if you apply excessive torque to the connectors. Do not
exceed the recommended torque indicated in the Electronic Calibration Module Reference
Guide (part number 85091-90009).
NOTE It is not critical which ECal module port (Port A or Port B) is connected to the network
analyzer test ports. The network analyzer detects where each ECal module port is connected
and uses the appropriate module data. If Port A is connected to Port 1 of the analyzer, the
calibration will be performed slightly faster.
7. Using an RF cable (or a microwave cable, as appropriate), connect the other port of the ECal module to
test port 2 of the analyzer.

Select the ECal Options

In addition to the standard ECal method, there are two options that you may want to use when performing
the electronic calibration. They are:
• ECal using a manual thru
Calibration using a manual thru is more accurate than calibrating using the thru internal to the ECal
module. (A zero-length thru is created by connecting the two test port cables together.) The improved
loss of the manual thru compared to the ECal module's thru, increases the accuracy of other error terms
in the correction. The accuracy of the overall calibration is improved. Manual thrus can only be used with
ECal modules having connectors of the opposite sex.
• ECal using isolation averaging
During the isolation measurement portion of ECal, you are actually measuring instrument crosstalk.
Typically, the data during this measurement is near the noise floor. (See also
Calibration" on page
When the crosstalk is near (or in) the noise floor, one way to reduce the noise is to turn on the isolation
averaging. When the random noise of the instrument is averaged, its magnitude declines. As the energy
of the trace is averaged, the displayed data becomes smoother. When the random noise is reduced, the
Figure 6-21.
6-4.)
Calibrating for Increased Measurement Accuracy
Calibrating Using Electronic Calibration (ECal)
"Omitting Isolation
6- 59