HP 8901B Operation And Calibration Manual page 310

Model 8901B
Operation
Finer Resolution for dB Measurements
Special Function.32.1 enables a resolution of 0.001
dB. For
audio frequency measurements, this special
function enables a resolution of 0.1 Hz for frequencies from 100 to 250 kHz instead of the normally
displayed resolution of 1 Hz. The selection of Special F'unction 32.0 or 32.1 is maintained through
instrument power down.
32.0 Power is displayed with the normal measurement resolution of 0.01
dB.
32.1 Power is displayed with a measurement resolution of 0.001
dB.
32.2 Displays 0 if the normal measurement resolution is enabled (32.0
SPCL)
and displays 1 if a finer
resolution is enabled (32.1).
Modulation Flatness
When used in conjunction with track mode tuning, the Ratio function makes checking modulation
flatness with respect to RF frequency very convenient. (Refer to R F Bequency Zbning on page 3-115
for a discussion of track mode tuning.)
Setting Measurement Limits
The ratio reference can also be entered as a limit reference. (Refer
to L i m i t
on page 3-219.)
Common Ratio Measurements
The following list provides some useful references for common ratio measurements:
0
To display broadcast
FM
deviation relative to the common standard of 75 kHz, use 75 and
0
To display
@M
in degrees, enter a value of 1.745 and select linear units.
0
To display
AM
as
dB
down from the carrier, enter a value of 200 and select logarithmic units.
0
To display rms calibrated average as true average, enter a value of 111.07 and select linear
0
To display rms calibrated average as peak, enter a value of 70.7 and select linear units.
linear units.
units.
This special function is not available with firmware date codes 234.1985 and below.
(To
display the firmware date code, select
42.0 SPCL.) To order a
ROM
set that contains this special function, contact the nearest HP sales office.
3-218
Ratio and Log/Lin