The calibration process determines the minimum frequency at which the ED722 will operate.

1. Set the [RATE] control to minimum
2. Set P4 to its centre position
3. Fit jumper JP1 in to the 'CAL' position
4. Monitor the [TRI-SAW] output using a multimeter
5. The output will exhibit a tendency to drift positive or negative and the voltage will eventually settle at +12V or -12V
6. Reset the output voltage by momentarily shorting JP2
7. Adjust P4 until the voltage remains stable with minimal drift for a period of several seconds
8. Repeat steps (6) and (7) until the drift is only a few millivolts over several seconds
9. Fit JP1 in to the 'RUN' position and ensure JP2 is open