- Recall Defaults.
- Connect a stable 10 MHz signal (e.g REF OUT from another counter/analyzer) to input A. Connect a 10 MHz, 100 mVRMS, (0.28 Vp-p) signal from the LF synthesizer to EXT REF. Select Ext Ref. from the Timebase Oscillator setting menu
- The display should show 10 MHz.
- Change the external reference frequency to 5 and 1 MHz.
- The counting should continue, and the display should still show 10 MHz.