Direct Sampling Remarks - Agilent Technologies 3458A User Manual

Direct Sampling
Remarks
138 Chapter 5 Digitizing
sampling, the minimum possible interval between samples is 20µs.
Figure 30. Direct sampling
•
You cannot use autorange for direct-sampled measurements; you must
specify the range as the first parameter of the DSAC or DSDC command
(max._input parameter). The max._input parameters and the ranges they
select are:
max._input Parameter Selects Range SINT Format DINT Format
0 to .012
>.O12 to .120
>.120 to 1.2
>1.2 to 12
>12 to 120
>120 to 1E3
Notice that when using the DINT memory/output format, the full scale
values for direct-sampling are 500% (5 times) the ranges of 10mV,
100mV, 1V, 10V and 100V. This is particularly important to consider
when specifying the percentage for level triggering. When specifying the
level triggering voltage, use a percentage of the range. For example,
assume the input signal has a peak value of 20V and you are using the
10V range. If you want to level trigger at 15V specify a level triggering
percentage of 150% (LEVEL 150 command). (The slew rate of the
multimeter's amplifiers may be exceeded when measuring a signal with
a frequency >2MHz and an amplitude >120% of range; signals £120% of
range with frequencies up to 12MHz do not cause slew rate errors.)
•
The multimeter's triggering hierarchy (trigger arm event, trigger event, and
sample event) applies to direct-sampling. This means that these events must
occur in the proper order before direct sampling begins. Refer to Chapter
4 for more information on the triggering hierarchy. For direct sampling,
you can use either the TIMER sample event and the NRDGS n,TIMER
command; or the SWEEP command (SWEEP is the simpler to program).
The NRDGS and SWEEP commands are interchangeable; the multimeter
10mV 12mV
100mV 120mV
1V 1.2V
10V 12V
100V 120V
1000V 1050V
Full Scale
50mv
500mV
5.0V
50V
500V
1050V