HP 8901B Operation And Calibration Manual page 308

Operation Model 8901B
LOCAL
(keystrokes)
-
(program codes)
2. Set the display to the desired reference value, either
0
adjust the signal parameter being measured for a display equal to the desired
0
enter the reference on the numeric keys. (If the reference value is to be negative, select
reference, or
minus; that is, the Blue Key, then the decimal key.)
3 . Select RATIO. The display will show the measurement result relative
to
the reference.
To use the Previous Ratio function to restore a previously-entered ratio reference:
1. Select the desired Measurement mode.
2. Select PREVIOUS RATIO (Blue Key, RATIO). The display
will
show the measurement result
relative
to
the original ratio reference. (The Modulation Analyzer uses the previous ratio reference
regardless of what Measurement the instrument was in when the ratio reference was entered and
regardless of the current Measurement mode.)
To display the ratio (or previous ratio) reference, key in 11.2 SPCL.
r D : y
E l
Y
Display
The displayed measurement result is
100%
REL if linear units are selected or 0
dB
REL if logarithmic
units are selected. (The display will normally vary about these nominal values due
to
noise and the
typical one-count uncertainty in the measured result.)
If it is desired to scale FM measurement results relative to 50 kHz, set the Measurement mode to FM.
LOCAL
(keystrokes)
-
(program codes)
50
R1
Data
l L
Display
If, as in the previous example, 35.35 kHz
FM
deviation was measured, the displayed measurement
result will be 70.7% REL if linear units are selected or -3.01
dB
REL
if
logarithmic units are selected.
3-216
Ratio and Log/Lin