Pendulum CNT-91R User Manual

Measurement Control
the time between each sample is ap-
proximately 104-108

s.
■ Repetitive Sampling Profiling
The measurement setup just described will not
work when the profiling demands less than 4
s intervals between samples.
How to do a VCO step response profiling
with 100 samples during a time of 10 ms.
This measurement scenario requires a repeti-
tive input step signal, and you have to repeat
your measurement 100 times, taking one new
sample per cycle. And every new sample
should be delayed 100

s with respect to the
previous one.
The easiest way to do this is by means of
a controller, e.g. a PC, although it is
possible but tedious to manually set and
perform all 100 measurements.
The following are required to setup a mea-
s
urement:
—
A repetitive input signal (e.g., frequency
output of VCO).
—
An external SYNC signal (e.g., step volt-
ag
e input to VCO).
—
Use of arming delayed by a preset time
(e.g., 100, 200, 300

s
).
See Fig. 5-16 and Fig. 5-17.
When all 100 measurements have been made,
the results can be used to plot frequency ver-
sus time. Note that the absolute accuracy of
the ti
me scale is dependent on the input signal
itself. Although the measurements are armed
at 100 s  100 ns intervals, the actual start of
measurement is always synchronized to the
first input signal trigger event after arming.
The TimeView™ software package will do
this measurement quickly and easily.
Fig. 5-16
Setup for transient profiling of a
VCO.
Fig. 5-17
Results from a transient profiling
measurement.
USER MANUAL ● CNT 9x Series ● Rev.22 February 2020
5-13

Pendulum CNT-91R Specifications

General

Brand	Pendulum
Model	CNT-91R
Category	Measuring Instruments
Language	English