Giga-tronics 8003, Operation Manual

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Operation
Manual 20791, Rev. C, June 2001 2-13
The 8003 cannot take measurements with uncalibrated or disconnected sensors. A measurement that
uses an unavailable sensor will not be able to be specified. Softkey labels referring to a measurement on
an unavailable sensor will be in dim, dark blue. For example, if sensor C were uncalibrated or not
connected it would not be possible to zero sensor C, perform a path calibration involving sensor C, or
define any of the following measurements on the entry channel: C, A/C, B/C, C/A, C/B, A-C, B-C, C-
A, or C-B.
2.3.4 Absolute Power & Swept Capabilities
The absolute power measurement capability of the 8003 allows the instrument to make swept absolute
power measurements which can be graphically displayed and manipulated. This capability also allows
the 8003 to function as a CW power meter.
Any channel can be designated to take either swept or CW measurements. In this context, swept refers
to swept measurements meant to be plotted in graphic format. CW measurements will only be displayed
in character format in the channel summary area of the display screen.
Some of the swept measurements are not available in the CW mode and vice versa. As an example, no
cursor options are available in the CW mode. Therefore, if the entry channel is in the CW mode and
the cursor key is pressed, the softkey menu labels will change to the cursor key menu, but all the labels
will be dim, dark blue. If any of the softkeys are pressed, no action will occur. Another example is that
sensor difference measurements will not be available for swept measurements.
2.3.5 Graph & Readout Display Modes
There are times when a large numeric readout is more convenient than a graph. Because of this, the
8003 has two major display modes. One of these is the graphic display mode in which swept channel
measurements are graphically displayed. Summary information for swept measurements is displayed in
the channel summary information area. CW channel measurements cannot be displayed graphically but
can be displayed in the channel summary area.
The other display mode is data readout display. In the data readout mode, the results of CW channel
measurements are displayed in large characters in the middle of the display screen. There is no graphic
representation of data. Swept channel measurements have only their channel summary information
displayed in large characters.
2.3.6 Path Calibration Memory
Besides absolute, swept, and CW power measurements, the 8003 can make normalized measurements. A
normalized measurement is displayed relative to a path calibration made without the device under test.
In the 8003, each sensor has its own path calibration memory. There is also unrelated non-volatile
memory which can store measurement trace data from any channel for use on the same and/or any other
channel(s).
A path calibration will be performed when the instrument is commanded to perform a through path
calibration or a short/open path calibration. Path calibrations will be performed only for individual
sensors, one at a time. The path calibrations will be performed and stored by sensor, not by channel.
The 8003 allows the definition, by channel, of whether or not to use path calibrations. If it is specified
that path calibrations should be used on a channel, then the measurement of each sensor being used by
the channel is ratio’ed with its path calibration. If a sensor’s path calibration has been cleared, then the
use of the path calibration will have no effect on the sensor’s measurement.