Keysight Technologies 3458A Guide D'utilisation page 99

Table 3-7
Synchronous sampling conversion
The synchronous sampling conversion calculates the true RMS value from
samples, but requires that the input signal be repetitive (periodic). Synchronous
sampling has excellent, linearity and is the most accurate of the three methods.
Synchronous sampling is useful for measuring periodic waveforms in the
frequency range of 1 Hz to 10 MHz.
Synchronous sampling remarks
– For synchronous sampling, the multimeter uses the LEVEL sync source event
– When using the LEVEL sync source, it is possible for noise on the input signal
– The input signal is always DC-coupled for synchronous sampling regardless of
Keysight 3458A User's Guide
AC and AC+DC voltage measurement methods
ACV/ACDCV
measurement Frequency range
method
Synchronous 1 Hz - 10 MHz
Analog 10 Hz - 2 MHz
Random 20 Hz - 10 MHz
(default mode) to synchronize sampling to the input signal. If the input signal is
removed during a reading and does not return within a certain amount of time,
(the time limits are determined primarily by the AC bandwidth setting which is
discussed later in this section) the measurement method changes to random
sampling so that a measurement can be made. You can prevent the
measurement method from changing using the SSRC command. You can also
pace synchronous sampling to a signal on the Ext Trig connector using the
SSRC command. Refer to the SSRC command in
information and example programs.
to produce false level triggers and to cause inaccurate readings. For accurate
readings, ensure that your nearby environment is electrically "quiet" and use
shielded test leads. Enabling level filtering (LFILTER ON command) reduces
the sensitivity to this noise. Refer to the LFILTER command in
more information.
the specified ACV or ACDCV measurement function. When ACV is specified,
the DC components are mathematically subtracted from the reading. This is
Configuring for Measurements
Repetitive signal
Best accuracy
required
0.01%
0.03%
0.10%
Chapter 6
Read ings per
second
Min. Max.
Yes 0.025
No 0.8
No 0.025
for more
Chapter 6 for
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