FAQs from Rohde & Schwarz

Phase Synchronization of two HMF25XX units


I need two signals of the same frequency with a fixed phase shift between them. How can I realize that with two HFM25XX?


To synchronize two HMF units, the following steps are necessary:

One unit is the "Master" the other one is the "Slave".

Connect "10MHz REF OUT" of the Master with "10MHz REF IN" of the Slave. They are located at the rear panel. Now both units use the same reference clock.

One the front panel connect "TRIG OUTPUT" of the Master with "TRIG INPUT" of the Slave. Then the signals are synchronized in phase.

The following settings are necessary:


Press "MENU" --> Softkey "SYSTEM" --> TRIGGER and set "TRIG.OUTPUT" to "On"


Press "MENU" --> Softkey "SYSTEM" --> TRIGGER and set "TRIG.SOURCE" to "Ext"

Press "MENU" --> Softkey "SYSTEM" --> and set "CLOCK" to "Ext".

Now Softkey "SYNCHRO." becomes active. With the rotary knob select "AUTO" or "Manual"

AUTO: The Slave synchronizes automatically with the reference signal from the slave

Manual: The Slave synchronizes when the key "TEM/TRIG" is pressed

The two signals are now synchronized in phase. But it is not possible to set a defined phase shift.

There is a way to get a phase shift:

Slightly change the frequency of the Slave. You will see that the phase will shift now. As soon the desired phase shift is reached, set the frequency back to that of the Master. The phase shift will remain.