Keithley 2750 User Manual page 160

Model 2750 Multimeter/Switch System User's Manual
For voltage, current, and resistance, the filter window is expressed as a percent of range.
For example, on the 10V range, a 10% window means that the filter window is ±1V. For
temperature, the filter window is expressed as a percent of the maximum temperature
reading. The maximum temperature depends on which thermocouple is being used. For
example, for a Type J thermocouple, the maximum reading is 760°C; a 10% window
means that the filter window is ±76°C.
Filter type — There are two digital filter types: moving and repeating. The moving aver-
age filter uses a first-in, first-out stack. When the stack becomes full, the measurement
conversions are averaged, yielding a reading. For each subsequent conversion placed in
the stack, the oldest conversion is discarded, and the stack is re-averaged, yielding a new
reading. This process is depicted in
For the repeating filter, the stack is filled and the conversions are averaged to yield a read-
ing. The stack is then cleared and the process starts over
ter is used for scanning so readings from other channels are not averaged with the present
channel.
NOTE
The moving filter cannot be used when scanning. If a scan channel is set up to
use the moving filter, the filter will not turn on. Scanning is covered in
Range, Digits, Rate, Bandwidth, and Filter
Figure 4-2A.
(Figure
4-15
4-2B). The repeating fil-
Section 7.