6482-901-01 Rev. A / August 2012 Return to Section Topics 4-9
Model 6482 Dual-Channel Picoammeter / Voltage Source Reference Manual Section 4: Range, Digits, Speed, and Filters
Advanced filter: The advanced filter is part of the moving filter. With the advanced filter enabled, a
user-programmable noise “window” is used with the moving filter. The noise window, which is
expressed as a percentage of range (0 to 105 percent), allows a faster response time to large
signal step changes. As previously explained, if the readings are within the noise window, the
moving filter operates normally. If, however, a reading falls outside of the window, the stack is
flushed of old readings and filled with the new reading.
For example, assume the window is set to 10 percent and the 20 mA range is selected. Therefore,
the noise window is ±2 mA (20 mA × 10% = 2 mA). Also assume the first reading is 2 mA. During
normal filter operation, the stack is filled with that reading. If each subsequent reading is within
±2 mA of the previous reading, the filter operates normally. Now assume a 10 mA noise spike
occurs. This noise window violation causes the stack to flush out the old readings and fill it with 10
mA reading.
NOTE If the repeat or median filter is enabled, the moving filter operation will not start until after
the previous filter yields a reading. In other words, after a reading is yielded from the
repeat or median filter, that reading will then be sent to the moving filter stack.
Filter configuration
Using Table 4-5 and Figure 4-6 as a guide, configure the filter as follows:
NOTE The filter setting is global and affects both channels.
1. Press the CONFIG key and then the FILTER key to access the filter configuration menu.
2. Select AVERAGE-MODE, and then choose the REPEAT or MOVING filter.
3. Place the cursor on AVERAGE-COUNT and press the ENTER key to display the present aver-
age count for the filter.
4. Use the , , , and keys to display the count (1 to 100), and then press the ENTER key.
5. Place the cursor on ADVANCED and press the ENTER key. The blinking cursor will indicate
the state of advanced filter.
6. Use the or
key to place the cursor on the advanced filter selection (DISABLE or ENABLE),
and then press the ENTER key.
7. If you enabled the advanced filter, use the , , , and keys to select and display the
noise window (0 % to 105 %), and then press the ENTER key.
8. Place the cursor on MEDIAN RANK and press the ENTER key to display the present median
rank for the median filter.
9. Place the cursor on the rank value (0 to 5) and press the ENTER key. Note that a rank of 0 dis-
ables the median filter.
10. Press the EXIT key to return to the previous menu.
Filter control
When filtering is applied to the input signal, the FILT indicator will be on. The FILTER key is used
to control filtering. Pressing the FILTER key turns on the FILT indicator to indicate that the filter
configuration is being applied to the input. Pressing the FILTER key a second time turns the FILT
indicator off to indicate that filtering is turned off.
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