HP 8508A - Page 33

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Operation
3-7
MAKING
MEASUREMENTS
3-8
BASIC
MEASUREMENTS
Introduction
There
are
two
types
of
Input
Module
that
can
be
used
with
the
HP
8508A
Vector
Voltmeter
mainframe.
These
Input
Modules
are
the
HP
85081
High
Impedance
Input
Module
and
the
HP
85082
50
ohm
Input
Module.
The
HP
85081
High
Impedance
Input
Module
has
a
frequency
range
from
100kHz
to
1GHz.
This
Input
Module
has
high-impedance
probes
which
can
be
used
either
alone
or
with
accessories
to
make
in-circuit
measurements.
The
following
accessories
are
available:
HP
11570A
Accessory
Kit
(50
obm
accessories),
HP
10216A
Isolator
(probing
accessory),
HP
115776A
10:1
Divider
(probing
accessory).
The
HP
85082
50
ohm
Input
Module
has
a
frequency
range
from
300kHz
to
2GHz.
This
Input
Module
has
50
ohm
type-N
connectors.
Using
the
HP
85082
gives
you
a
higher
frequency
range
than
the
HP
85081
for
measurements
in
a
50
ohm
environment.
Getting
acquainted
with
the
Vector
Voltmeter
To
introduce
you
to
the
main
functions
of
the
HP
8508A,
here
are
a
few
simple
measurements
you
can
try.
You
will
learn
to
make
single
channel
voltage
and
power
measurements,
and
measure
the
vector
ratio
between
two
voltages.
a.
Measurements
with
probes
For
this
section,
measurements
are
made
on
a
printed
circuit
board
buffer
amplifier.
It
is
part
of
a
5S0MHz
source
assembly,
and
has
a
gain
of
approximately
14dB.
Probing
at
the
input
of
the
amplifier
(the
output
of
the
oscillator)
gives
a
reference
signal
and
probing
at
the
output
of
the
amplifier
will
give
the
amplifier
gain.
Use
the
integral
source
as
the
stimulus,
so
the
amplifier
will
be
tested
under normal operating conditions.
Source - : Amplifier
Figure
3-3.
Test
Assembly
With
Measurement
Points
3-9
/A