ing the IFD mode, the instrument may need to pause slightly
to fill in additional waveform data.
During the IFD mode, do not change the pulse width. If
the pulse width is changed, the IFD routine will reset and
start collecting data at the new pulse width.
The intermittent fault waveforms are stored in memory.
This is an important difference between the Model 3300
and other TDRs. While the waveform is in memory, there
are three important things to note;
1. The waveform can be adjusted as if it were a live
waveform.
2. Make sure the Model 3300 battery is fully charged.
In the IFD mode, if the instrument battery level goes
below a minimum safe level, the instrument will turn
itself off to prevent possible battery damage.
3. Waveforms can be stored and taken back to the
office for downloading to a serial printer for
archiving.
Storing an IFD Waveform
To store an IFD waveform, select Store from the pop-up
menu while in the IFD mode. The instrument will save the
intermittent waveforms in a dedicated IFD memory loca-
tion. If a waveform has been stored in the IFD memory,
the next time you enter the IFD mode, a prompt will ap-
pear to confirm you wish to overwrite the old waveform.
2.3.5 Zoom Control
The Horizontal Zoom control expands and contracts the
waveform around center screen. This control can be used
to closely examine a feature found using preset RANGE
operation or can be adjusted manually for complete con-
trol of the waveform display distance.