HP 8901B Operation And Calibration Manual page 286

Model
8901B
Operation
AM
Display Resolution vs. Modulation Output Sensitivity
In Automatic Operation, when the Modulation Output/Audio Input feature is used, the output
autoranges. Autoranging usually occurs between
3 . 5
and
4
Vpk, open circuit. Many variables, however,
affect the autorange limits and hence the displayed measurement resolution. The variables include:
type of modulation, audio detector, audio filtering, and FM de-emphasis. Special Function 2 permits
manual setting of the audio range.
The following table examines this relationship. (Refer to Audio Range on page 3-183 for more
information on modulation ranges.)
FM 4M
Display
Resolution
Modulation
output
(O/O)
(Vac/O/o) (Hz)
Sensitivity
D i
s
p I a y
Resolution
Modulation
output
Resolution Sensitivity
Display
Modulation
output
Sensitivity
(mVac/Hz) (radians) (mVac/radian)
0.001
0.01'
100 0.0001 10
0.1
-
0.1 10
0.001 1
I
'Available
onlv
with
750
us de-ernDhasis, Dre-disDlav.
0.01
0.1
0.1 0.01
BLOCK DIAGRAM
1 1
10 0.1
0.01 0.1
100 0.01 0.1 0.01
AM
MOOULATION
OUTPUTi
OEMOOULATOR
d
~ < M > ~ T ~ ~ ~
A t i n i n ~ ~ I D I I T
Modulation OutputlAudio Input Block Diagram
Modulation Output/Audio Input 3-189