Step Control Slave

Function Group FREQUENCY

Menu Map 2

Description This softkey lets you designate the synthesizer as the slave in a dual synthesizer measurement system. A dual synthesizer system (two-tone measurement system) facilitates accurate device characterizations by providing one timebase reference for both sources.

Figure S-l shows the connections required for a two-tone system. On the message line, the status message EXT REF appears indicating the synthesizer has an external timebase reference. The start and stop frequencies of the slave can be offset above or below those set on the master for fixed offset two-tone measurements.

To synchronize properly for swept offset measurements, the 0 to 10 volt sweep ramp must be actively sweeping on the slave. If a CW frequency is selected as the fixed LO frequency, the sweep ramp is deactivated and the proper synchronization does not occur. Select a center frequency with zero span to keep the slave’s voltage sweep ramp active and ensure proper synchronization.

For synthesized step sweep measurements, set the number of sweep points on the slave the same as on the master synthesizer. If the master synthesizer is connected to a network analyzer, the analyzer automatically sets the master synthesizer’s step size to match

the number of points displayed on the analyzer. Since the slave synthesizer is not connected to the analyzer, set the slave to match the master synthesizer. Allow the master to trigger the slave’s steps, set Step Swp Pt Tsig Ext on the slave synthesizer.

For ramp sweep measurements, on the slave set the sweep time equivalent to the master synthesizer. If the master is connected to a network analyzer, the slave’s sweep time is slightly longer than the master’s because the analyzer does not stop the sweep precisely on the last point. Use the following formula to determine the slave’s sweep time for a system controlled by an analyzer.

SweepTimeMaste, x 1.03 = SweepTimesl,,,

For fixed-offset ramp sweep measurements the same sweep time must be set on both the master and the slave. Since the master’s sweep time is typically determined by the measurement configuration, set the slave to match the master.

For more accurate ramp sweeps, select Sup Span Cal Always on both the master and slave synthesizers. When this feature is active it calibrates the frequency at the end of every frequency band.

S-66 Operating and Programming Reference

HP 8360

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