HP 8901B Operation And Calibration Manual page 330

Operation Model 8901B
6.
Automatic Level Control.
Use this special function
to
speed up the ALC response time or to disable
the ALC. (The faster ALC response time degrades
AM
accuracy at rates less than 1 kHz.) Disabling
the A X , in conjunction with the rear-panel AM Output connector, can be used to measure AM at
very low modulation rates. Disabling the ALC also permits measurement of absolute changes in AM
depth without regard to changes in carrier level.
6.0 Slow ALC (for
AM
rates greater than 20 Hz).
6.1 Fast ALC (for AM rates greater than 1 kHz).
6.2 ALC off.
7. RF
Frequency Resolution.
Use this special function
to
manually set the display resolution during
frequency measurements (including RF, IF, and LO frequencies). Note that with finer resolution,
measurement time increases
.
7.0 Automatic selection.
7.1 Resolution of 10 Hz.
7.2 Resolution of 100 Hz. (When using an external LO value greater than 20 GHz, 7.1 SPCL
7.3 Resolution of 1 kHz.
7.4
selects 100 Hz resolution.)
(Applies to RF F'requency measurements only; other measurements treat 7.4 as 7.1.)
Resolution of 0 . 1 Hz for input signals less than 10.1 MHz; resolution of 1 Hz for
signals
from 10.1 MHz through 1300 MHz. (When measuring frequencies as high as 1300 MHz,
measurement time with this resolution is approximately 20 seconds.)
8.Error
Message Disable Control.
Most combinations of Errors 01 through 04 can be disabled
.
or enabled
to
customize the behaviour of the instrument
to meet a particular set of measurement
requirements. When the Modulation Analyzer uses automatic selection of error messages, these
messages are selectively enabled, depending on the measurement being made,
to
assure the broadest
range of calibrated measurements. Error Message Disable Control on page 3-233 has a table that lists
the errors
8.0
8.1
8.2
8.3
8.4
8 . 5
8.6
8.7
8 . 8
that are automatically disabled during each measurement.
Automatic selection of disabled error messages.
Disables Error 01.
Disables
Errors
02 and 03.
Disables Errors 01, 02, and 03.
Disables Error 04.
Disables Errors 01 and 04.
Disables Errors 02, 03, and 04.
Disables Errors 01,02,03, and 04. Performs the same function as
DISABLE
ERROR (Blue
Key, RANGE HOLD).
Enables Errors 01,02,03, and 04. This ensures that the output from MODULATION OUT-
PUT is safeguarded for most measurements. Some tuned, non-modulation measurement
modes (such as frequency) do not completely safeguard the signal fidelity at this output
since accurate demodulation
is
not the primary goal of that measurement mode.
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.
3-242