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The Tuning Settings balance LO measurement speed versus accuracy. You can see that accuracy is becoming compromised when noise starts to appear on the measurement trace.
Scroll up to learn more about the Embedded LO measurement process.
Embedded LO Mode On Check to enable measurement of the Embedded LO.
Tuning Point Select, or specify, the data point in the mixer sweep that will be used to find the embedded LO frequency. If a marker is enabled, that data point can be used. For broadband and Precise sweeps, choose a point in the mixer sweep where noise is least likely to be found, such as the point of highest gain. This is generally the center of a sweep or the center of a filter if used.
LO Frequency Delta The absolute difference between the measured embedded LO frequency and the LO setting that is entered in the Mixer Setup dialog. This value is updated each time the embedded LO frequency is measured. Entering a value is a way to change the LO frequency on the mixer setup without invalidating the calibration.
Reset Set the LO Frequency Delta back to 0 Hz.
Find Now The PNA finds and measures the actual LO frequency using the current dialog settings. This data is displayed in the Status box.
Tuning Settings These settings determine the amount of time spent versus the degree of accuracy to which the LO Frequency is measured. You can see that accuracy is becoming compromised when noise starts to appear on the measurement trace.
Reset Set all Tuning Settings back to the defaults.
Broadband and Precise Does the entire tuning process for each background sweep. See the Overview for more information.
Precise only Does NOT perform broadband tuning on each sweep. Use this setting when the embedded LO is stable. The signal (after broadband) must be within ½ the tuning IFBW. If the signal will always be within ½ the IFBW, broadband tuning is not needed. Most satellite components are within 3 kHz absolute so might not need broadband tuning.
Disable tuning Only the previously measured LO Frequency Delta is applied to the reference mixer LO and PNA receivers.
Sweep Span Narrowing the sweep span limits the number of data points that are measured in the broadband sweep and makes the measurement faster. Sweep span should be less than 14 MHz. The resolution of the broadband mode is the tuning IFBW.
Max Iterations The maximum number of Precise sweeps to make. When this number is reached, the final measurement is used.
Tolerance When two consecutive Precise measurements are made within this value, the final measurement is used. If this is not achieved within the Max Iterations value, then the last measurement is used. This is the best of the 'Tunings settings' to change to improve accuracy.
Tuning IFBW IF Bandwidth used for Broadband and Precise tuning sweeps. This sets the resolution in the Broadband sweeps and sets the max error (1/2 IFBW) for precise tuning. The larger the IFBW, the faster the sweep, but the signal may not be found.
Tune every Set the interval at which tuning is performed before a measurement sweep. 'Tune every 3 sweeps' means that every third measurement sweep is preceded by tuning sweeps. If the embedded LO drifts, or if regularly changing DUTs, use 'Tune every 1 sweep'.
Status Allows textual and graphical representation of the Embedded LO measurement sweeps.
Clear Removes the text information currently being displayed.
Graph Launches the following graphical (spectrum analyzer type) display sweeps of the latest embedded LO measurement.
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