14
The items on this menu are:
VNA MODE (Dual Port Models Only)
This option will allow you to select the operating mode for the VNA function of the instrument. There
are two possible selections (use the
button ):
S11
- This enables single-port impedance analysis, including impedance magnitude and
impedance phase. Used to analyze single-port devices such as antennas and terminated
feed lines.
S21
- This enables two-port analysis, primarily for gain measurements on two-port networks
such as filters and attenuators.
CALIBRATIONS
This option selects the type of calibration method to use for measurements. There are two possible
selections (use the
button):
BROADBAND
- When BROADBAND is selected, instrument calibration is performed over the
MRI-
3000’s entire frequency range of 100KHz to 450MHz (See Section 4 for procedures).
After that, any frequency range can be selected without having to re-calibrate. This form of
calibration will provide good accuracy with the convenience of not having to recalibrate for
each frequency or bandwidth change. For the most accurate measurements select
“Frequency Specific” (below).
FREQUENCY SPECIFIC
- This calibration mode will require recalibration with any change in
frequency or bandwidth (Span). In this mode, the MRI-3000 will automatically go to the
calibration screen prompts when any frequency changes are entered. The measurements,
however, will be more accurate than using Broadband Calibration.
BROADBAND CAL
This option will initiate the broad-banded calibration cycle. This calibration is stored in the unit, and is
valid anywhere in the units operating range. The Broadband calibration may be performed with or
without a test lead and/or adapters attached. It will display a series of calibration screens prompting
the user to attach the Open, Short, and Load Terminators in turn. Press ENTER for each one to
complete the process. The Open prompt can use the open end of the test lead, adapter or
instrument’s N connector. Attaching an Open Terminator is optional, although recommended as it
gives better accuracy overall. Once this process is complete, the calibration data is stored, and the
instrument will be placed in BROADBAND calibration mode. See Section 4 for more information on
calibration steps. For best results allow unit to warm-up 5-10 minutes and use the precision 3 way
Open, Load and Short.
SWEEP ENABLE
Press ENTER to re-enable the sweep. When the sweep is running, the LED above the SWEEP/CW
button will flash. This option is available as the MRI PC Vision software may, during normal
operation, turn the MRI-3000's sweep OFF. If the sweep LED is not blinking, use this option to turn
the Sweep back ON before starting calibration or testing.
GRAPH SELECT
Pressing <ENTER> with this menu item selected, will switch the display between wide and narrow-
format graphs. The narrow format graph setting also features large-font measurement format. This
selection is NOT applicable in S21 mode.
GRID LINES
Pressing <ENTER> with this menu item selected will change the number of grid lines on the graph.
You can select between 2x2, 2X4, and 2x5 divisions on the chart.
