Keysight Technologies 3458A Guide D'utilisation page 94

3 Configuring for Measurements
When using the APER command, the multimeter does not average readings for
NOTE
long integration times as it does with the NPLC command. For example, if you
specify 60 = PLCs (1 second of integration time at a 60 Hz = line frequency) using
the NPLC command, the multimeter averages six 10 PLC readings. If you specify
1 second of integration time using the APER command, the multimeter
integrates a single reading for 1 second.
With the APER command, you can specify integration time from 500 ns to 1 s in
increments of 100 ns. The APER command is most commonly used when
sampling a specific part of a signal (such as a pulse) or for digitizing. You can also
use the APER command to reject a noise signal of a specific frequency from the
input signal. To do this, set the integration time equal to an integral multiple of
the period of the signal to be rejected. For example, to reject noise at 100 Hz
(period = 10 ms), specify an integration time of 10 ms, 20 ms, 30 ms, etc.
Specifying resolution
You specify the measurement resolution as the last parameter of a function
command (FUNC, ACV, DCV, etc.) or the RANGE command.
called %_ resolution since you specify it as a percentage of the command's
max._input parameter (see
multimeter multiplies the specified %_resolution parameter times the max._input
parameter to determine the measurement resolution. To compute the
%_resolution parameter, use the equation:
For example, suppose the maximum expected input is 10 VDC and you need 1
mVDC of resolution. The equation evaluates to:
If you default the %_resolution parameter, the integration time will be that
specified by the last APER or NPLC command executed.
For DC or ohms measurements (and analog AC measurements), resolution is
determined by the A/D converter's integration time. When you specify a
resolution, you are actually indirectly specifying an integration time. Since the
[1] You can also specify resolution using the RES command. Refer to the RES command in
94
%_ resolution = (actual resolution/maximum input)
%_ resolution = (0.001/10)
for examples showing its usage.
Specifying the range
×
100 = 0.01
[1]
This parameter is
earlier in this chapter). The
×
100
Keysight 3458A User's Guide
Chapter 6