Anritsu MG3641A - Manual (Page 49)

SECTION 4 OPERATING INSTRUCTIONS
4.4.2 Displaying the Frequency Relative Value
To display a frequency in a relative value referred to the current frequency defined as reference (0 Hz), you press the
[Rel Freq] key. The lamp of the key will come on, causing the Frequency indicator to display +0 Hz.
While a frequency relative value is on display, all frequency settings made via the number keys, step keys and the
rotary knob will be treated as relative frequency settings.
To clear the frequency relative value display, turn the lamp off by pressing the [Rel Freq] key again.
If you need to verify the actual output frequency while a frequency relative value is on display, press the [Shift] key
and, then, keep on holding down the [Rel Freq] (Cur Dspl) key. This will allow the actual output frequency to
appear temporarily on the display.
[Rel Freq] key
MG3641A/MG3642A front panel
[Shift] key