Tektronix P6723 - Manual (Page 21)

P6701B and P6703B Performance Verification
P6701B, P6703B, and P6723 Service Manual 11
3. Set the oscilloscope for 5 us/div on the horizontal scale and 5 mV/div (or
5 uW/div) for the vertical scale. Trigger the scope on the negative edge of
the trace and set ground to the middle of the screen. This is equivalent to
1%/div.
4. Check that the OFF level of the square wave at approximately 5 us after the
90% fall time point is within 16 mV (8%) of the ground level (center line).