HP 8753D - Page 270

The
Built-In
T
est
Set
The
HP
8753D
features
a
built-in
test
set
that
provides
connections to
the test
device,
as well
as
to
the
signal-separation
devices
.
The
signal
separation devices
are needed
to separate
the
incident
signal
from
the
transmitted
and
reected
signals
.The
incident signal
is applied
to the
R
channel
input
through
a
jumper
cable
on
the front
panel. Meanwhile
,the
transmitted and
reected
signals
are
internally
routed
from
the
test
port
couplers
to the
inputs of
the A
and B
sampler/mixers
in
the
receiver
.
P
ort
1
is
connected
to the
A input
and port
2is
connected
to
the
B
input.
The
test
set
contains
the
hardware
required
to
make simultaneous
transmission and
reection
measurements
in
both
the
forward
and
reverse
directions
.An
RF path
switch in
the
test
set
allows
reverse
measurements
to
be
made
without
changing
the connections
to the
test device
.
The
Receiver Block
The
receiver block
contains
three
sampler/mixers
for
the
R,
A,
and
B
inputs
.
The
signals
are
sampled,
and
mixed
to
produce
a
4
kHz
IF
(intermediate
frequency).
A
multiplexer
sequentially
directs
each
of
the
three
signals
to
the
ADC
(analog
to
digital
converter)
where
it
is
converted
from
an
analog
to
a
digital
signal.
The
signals
are
then
measured
and
processed
for
viewing on
the display
.Both
amplitude
and
phase
information
are
measured
simultaneously
,
regardless of
what is
displayed on
the analyzer
.
The
Microprocessor
A
microprocessor
takes
the
raw
data and
performs
all
the
required
error
correction,
trace
math,
formatting,
scaling,
averaging,
and
marker operations
,
according
to
the
instructions
from
the
front
panel
or
over
HP-IB.
The
formatted
data
is
then
displayed.
The
data
processing
sequence
is
described
in
\Data
Processing"
later in
this
chapter
.
Required
P
eripheral
Equipment
Measurements
require
calibration
standards
for
vector
accuracy enhancement
(error-
correction), and
cables for
interconnections
.
Model
numbers
and
details
of
compatible
power
splitters,
calibration kits
,
and
cables
are
provided
in
Chapter
11,
\Compatible
P
eripherals
."
Application and Operation Concepts 6-3