Agilent Technologies 4395A - Page 237

Measuring
the
Noise
Level
Measuring
the
Noise
Level
1.
Press 4
F
o
rmat
5
.
2.
Choose
N
NN
NN
NN
NN
NN
N
N
N
N
N
N
NOISE
.
3.
Press 4
Scale
Ref
5
. Then
press
4
+
5
until the
noise
trace
gets
close
to
the
reference
level.
4.
Press
4
Bw/Avg
5
.
Then
press
N
N
N
N
N
N
N
N
N
N
N
N
N
N
NN
NN
NN
NN
N
N
N
N
VIDEO
BW
.
5.
Press
4
+
5
to
atten the
noise trace
.
6.
Press
4
Ma
rk
er
5
.
Then turn
the
and
read
the normalized
noise level.
The
marker
readout
unit
becomes
\dBm/Hz"
and
is normalized
by the
1Hz
equivalent
noise
bandwidth
(ENBW).
T
o
convert
the
ENBW,
see the
\Converting to
a
Dierent
Unit
of
Equivalent
Noise
Bandwidth
"
procedure
.
Figure
8-19.
Noise
Readout
Note
Switching the
display to
a noise
format
causes
the
4395A
to
perform
detection
in sample
detection mode
. Subsequently
returning the
format
to
4
F
o
rmat
5
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
NN
NN
NN
NN
N
SPECTRUM
causes
the
4395A
to
perform
detection
in
positive
peak
detection
mode
.
This is
true even
if you
have selected
the negative
detection mode
before switching
to the noise format.
Converting to a Dierent Unit of Equivalent Noise Bandwidth
1. Calculate the conversion factor using the following equations with displayed units:
Unit Use
dB m=H z
K =10
logBW
dB V =
p
Hz , dB V =
p
Hz K =20 logBW
W=H z K =1 =B W
V=
p
Hz K =1 =
p
BW
2. Where, BW is the target equivalent noise bandwidth.
Analyzing the Measurement Results 8-35