Minimizing Signal Noise - Fluke 91 Series II User Manual

Introducing The ScopeMeter Test Tool 1 - 5

MINIMIZING SIGNAL NOISE

In general, using your test tool on battery power only will
minimize noise pickup. Using the 10:1 probe will help in
noise rejection.
If you use the Power Adapter (PM8907), connect a test
lead from the black 4-mm banana jack COM (common) to
the measurement common (ground) of the system under
test. This technique reduces or eliminates any power line
related noise.