Measurement
Overview
The
HP
84125C
microwave
EMI
measurement
test
system
may
be
used
for
a
variety
of
measurements
.
T
o
assure
the
best,
most
accurate
measurements
of
your
product,
you
should
read
and
review
the
required
product
regulations
.
The
following
is
a
brief
description
of
how
to
use
the
system
to
test
a
product
to
the
FCC
P
art
15
regulation.
A
detailed
measurement
example
for
measuring
an
intentional
radiator
has
been
provided
in
Chapter
6.
Current
FCC
regulations
specify
that
harmonic
emissions
measured
above
1
GHz
on
wireless
transmitters
should
be
below
54
dBV/m
using
average
detection
at
a
distance
of
3
meters
.
At
higher
frequencies
,
cable
loss
and
antenna
factors
bring
the
inherent
system
noise
level
close
to
the
regulatory
limit.
T
o
improve
the
signal-to-noise
ratio
,
the
FCC
allows
positioning
the
measuring
antenna
at
a
distance
closer
than
3
meters
.
The
correction
to
be
applied
is
described
in
FCC,
P
art
15.31
(f)(1)
which
states:
\At
frequencies
equal
to
or
above
30
MHz,
measurements
may
be
performed
at
a
distance
other
than
what
is
specied
provided:
measurements
are
not
made
in
the
near
eld;
and,
it
can
be
demonstrated
that
the
signal
levels
needed
to
be
measured
at
the
distance
employed
can
be
detected
by
the
measuring
equipment.
Measurements
shall
not
be
performed
at
a
distance
greater
than
30
meters
unless
it
can
be
further
demonstrated
that
measurements
at
a
distance
of
30
meters
or
less
are
impractical.
When
performing
measurements
at
a
distance
other
than
what
is
specied,
the
results
shall
be
extrapolated
to
the
specied
distance
using
an
inverse
linear
distance
extrapolation
factor
(20
dB/decade)."
This
would
translate
to
measuring
to
a
limit
of
approximately
64
dBV/m
at
a
distance
of
1
meter
.
Therefore
,
we
recommend
that
you
rst
make
a
measurement
at
a
distance
of
1
meter
to
the
64
dBV/m
limit
line
with
peak
detection.
Using
a
1
meter
measurement
will
improve
the
signal-to-noise
ratio
making
it
easier
to
detect
emissions
.
Signals
with
a
peak
value
above
the
64
dBV/m
limit
line
will
need
to
be
remeasured
using
average
detection.
1-2
Product
Description
Содержание 84125C
Страница 7: ......
Страница 13: ......
Страница 19: ...Figure 2 1 HP 84125C System Dimensions 2 4 Speci cations and Characteristics ...
Страница 23: ...Declaration of Conformity Figure 2 5 Declaration of Conformity 2 8 Speci cations and Characteristics ...
Страница 45: ......
Страница 55: ...DLP Softkey Menu Figure 5 1 DLP softkey menu 5 2 System Interface ...
Страница 65: ......
Страница 71: ......
Страница 85: ......
Страница 91: ...8 6 Customer Support ...
Страница 97: ......