HP HP 8712ES, Руководство пользователя, Страница: 267 / 507

ES User’s Guide 6-21
Calibrating for Increased Measurement Accuracy
Calibration Choices
A one-port calibration prompts you to connect an open, a short, and a
load to port 1 (for measuring S
11
), or port 2 (for measuring S
22
). The
analyzer measures each standard across the frequency band you have
defined, using the number of points you have defined. The measurements
of these standards are used to remove systematic errors caused by
directivity, source match, and frequency response.
This method of calibration is the most accurate form of error correction
for measuring two-port devices since it can account for all of the major
sources of systematic error. This calibration prompts you to connect a
through standard between port 1 and port 2, and then to connect an
open, a short, and a load to port 1. Then it prompts you to connect an
open, a short, and a load to port 2. The analyzer measures each standard
across the frequency band you have defined, using the number of points
you have defined. The measurements of these standards are used to
remove systematic errors caused by frequency response, load match,
source match, and directivity. When a two-port calibration is selected,
the analyzer automatically measures all four S-parameters. To quickly
view each of the four S-parameters press
,
and then press the desired S-parameter softkeys under the or
menu. You may need to adjust the scaling to view each of the
S-parameters.
NOTE
When toggled on, the softkey allows you to remove
systematic errors caused by crosstalk. To select it, press
. A two-port
calibration always measures the same parameters, regardless of the
setting of
. Therefore, no further measurements of
calibration standards are required when you enable the isolation
calibration feature. When toggled ON, this feature will change the
analyzer’s calculations before displaying the data. Crosstalk can be a
problem with high-isolation devices and high-dynamic range devices.
Since this isolation calibration adds noise to the error model, you should
only select it if it is really needed.
User 1-Port
User 2-Port
MENU
Trigger Hold
MEAS 1
MEAS 2
Isolation on OFF
CAL
User 2-Port Isolation on OFF User 2-Port
Isolation on OFF