Using The Four-Parameter Display; Four-Parameter Display And Calibration; Lb View Aii Four S-Parameters Of A Two-Port Device - Agilent Technologies 8719D User Manual

Using the Four-Parameter Display

All four S-parameters of a two-port device may be viewed simultaneously by enabling auxiliary
channels 3 and 4. Although independent of other channels in most variables, channels 3 and
4 are permanently coupled to channels 1 and 2 respectively by stimulus. That is, if channel 1
is set for a center frequency of 200 MHz and a span of 50 MHz, channel 3 wiII have the same
stimulus values.
Channels 1 and 2 are referred to as primary channels, and channels 3 and 4 are referred to as
auxiliary channels.

Four-Parameter Display and Calibration

A full two-port calibration must be active before an auxiliary channel can be enabled. The
following measurement example uses a full two-port calibration covering the entire frequency
range of the analyzer, which is then narrowed to the range of the DUT (device under test)
using interpolated error correction. Refer to the "Full Two-Port Error-Correction" procedure in
Chapter 5.
Interpolated error correction is a useful feature which allows you to select stimulus parameters
which are subsets of a calibration which originally covered a wider frequency range.
Interpolation retains the calibration for the new stimulus parameters as long as they fall within
the range of the original calibration. Refer to Chapters 5 and 6 for a full description of error
correction.
The status notation CA will appear on the display if interpolated error correction is on. This is
normal. Refer to "Status Notations" in Chapter 2.
A full two-port calibration can also be recalled from a previously saved instrument state. See
"Recalling a File" in Chapter 4.
The device used in this measurement example is a bandpass filter with a center frequency of
134 MHz.
1.
Press w
If a full two-port calibration has been performed or recalled from a previously saved
2.
instrument state, go to step 5. If not, proceed to the next step.
Set the stimulus values for the DUT. For this example, a center frequency of 134 MHz
3.
and span of 45 MHz were selected, and the IF bandwidth was left at its default value of
Hz.
3700
Perform a full two-port calibration on your analyzer. Refer to "Full Two-Port
4.
Error-Correction" in Chapter 5.
Connect the DUT to the analyzer.
5.
Press [K] to select the type of display of the data. This example uses the log mag
6.
format.
If channel 1 is not active, make it active by pressing c-1).
7.
8.
Making Measurements 2-9