Leader Electronics Corp. LDC-824 - Setting of Input Sensitivity

4.4 Setting of input sensitivity
(1)
Input sensitivity and noise
The
input
sensitivity
of
LDC-824(S)
can
be
selected
from
0.02Vrms,
or
0.2Vrms,
in
order
to
measure
input
signals
of
wide
voltage
ranges.
When
a
large
signal
is
applied
to
the
input
at
the
higher
input
sensitivity,
the
noise
included
in
the
input
signal
may
induce
miscounting.
In
this
case,
reduce
the
input
sensitivity
to
the
appropriate
input
range
as
listed in Table 4-4-1. This minimizes errors.
0.02Vrms 0.02 — 0.2Vrms
0.2 — 2Vrms
Table 4-4-1
Automatic Trigger Level Function
The trigger level of LDC-824(S) is designed to function automatically in 80MHz frequency
range. |
Trigger level is set automatically to a level (Fig. 4-4-2) of input voltage that is divided
equally into three parts. The functional range of automatic trigger level shall be, for
instance, between 20mV and 200mV input voltage when preset sensitivity is 20mV. When
it is preset at 200mV, the input voltage range for automatic trigger level is between 200mV
and 2V. In the case the above-mentioned input voltage range is exceeded, the trigger level
is fixed at 200mV position when preset at 20mV sensitivity and is fixed at 2V position
when preset at 200mV sensitivity.
In accordance with all these, correct signal counting can be conducted (Fig. 4-4-2) without
miscounting when noise voltage is 50% or less of the signal voltage and it is within the
range of automatic trigger level.
In addition, measurement of pulse signals with large duty ratio can be conducted with
ease, as the trigger level is set automatically at the optimum level, even if it has been
necessary to adjust the trigger level for the pulse signal measurement.
Positive Peak
Noise
Upper Trigger Level
Lower Trigger Level
Input Signal
Negative Peak
Shaped Signal FLL.
Fig. 4-4-2