30
.Normalization
Select CH I or CH2
Press INPUT
Model 8754A
8750A:
Select CHI
or
CH2
then
press STORE INPUT
or
INPUT-MEM (trace moves
to
center graticule).
Connect test device.
8754A:
Set
CRT
(reference position line
to
center graticule).
Select measurement
(A/R,
B/R,
PHASE
B/R).
Connect
standard
(short, through,
or
standard
device).
Set Scale/division same
as
for measurement.
Adjust
OFFSET
vernier so
that
trace
is
fully on the CRT.
It
is
important
that
scale/division
not
be changed
after
the reference response
is
stored. Also, the 8750A in-
corporates
±
50070
vertical digitizer overrange. This means
that
traces which exceed the vertical display
range by
up
to
four
major
divisions
can
be stored for use as the reference even though the trace appears
to
be truncated
at
the upper
or
lower graticule line.
If
the reference trace exceeds ±
50070
overrange the nor-
malized display will
not
be correct.
The typical use for normalization
is
to
remove the frequency response characteristic
of
the measurement
setup from the measurement. A normalized display shows the difference between the frequency response
of
the measurement standard and the response
of
the test device directly
as
deviation from a straight line.
Thus, normalization replaces conventional methods, such
as
using a grease pencil on the face
of
the
CRT,
as
the preferred
method
of
measuring and adjusting devices
to
match a standard response.
When
STORE
INPUT
is
pressed, the current displayed trace, except for frequency markers,
is
transferred
to
reference memory. Pressing
INPUT-MEM
displays the difference between the reference trace
and
the
current measurement as deviation
from
a straight line
at
the center graticule.
If
the current trace
is
identical
to
the reference trace, then the normalized trace
is
a flat line
at
the center horizontal graticule.
RECALL
can be pressed
to
display the stored reference trace instead
of
the measurement trace,
if
desired.
Digital Storage
When the device response characteristic requires a slow sweep
to
avoid distortion
of
the measurement, use
digital storage
to
provide a flicker-free display.
Each
measurement trace
is
digitized
and
stored
at
the 8754A sweep rate then
output
to
the
CRT
at
a fixed
display rate. This provides display
of
the complete measurement trace regardless
of
the network analyzer
sweep time. Rectangular traces are digitized
at
256 points
on
the x-axis
and
512 points
on
the y-axis (32
points per
major
vertical division; 256 points
to
achieve ±
50070
overrange).
L
Storage Normalizer
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
To Next Page
Loading...
