HP 8901B

Model 8901B Operation
18. (-) (Blue Key) enables input data to be entered as a negative value.
19. RANGE HOLD freezes the current ranges being used by the Modulation Analyzer. [See
Range Hold.]
20. Blue Key is a shift key that enables some keys to have two different functions. Any function
printed in blue can be selected when the key associated with
it is pressed after the Blue Key.
(The Blue Key flashes
at the current measurement rate whenever it is pressed.)
21. DISABLE ERROR (Blue Key) disables Error 01 through Error 04. [See Error Message
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
Disable Control.]
LOG/LIN causes measurements to alternate between logarithmic and linear units. [See Ratio and
LoglLin.
]
dB EXT ATTEN (Blue Key) enables level measurements to be offset with external attenuation
or gain. [See
External Attenuation.]
RATIO and PREVIOUS RATIO (Blue Key) cause the current measurement to be compared to a
reference. [See Ratio and LoglLin.1
Operating Information pull-out cards are quick operating references that list Special Function,
HP-IB, and Error codes, show a simplified block diagram for the Modulation Analyzer, and
provide basic information for
RF Power and AMFM Calibration.
DETECTOR keys select the audio detector used to measure the modulation. [See Audio Detectors,
Audio Distortion and Level, SINAD.]
1 kHz DISTN (Blue Key) and 400 Hz DISTN (Blue Key) enable the Modulation Analyzer to
make audio measurements on either 1 kHz or 400 Hz audio signals. [See Audio Distortion and
Level, SINAD.]
CALIBRATION AMFM OUTPUT makes available a precisely modulated signal used to improve
the Modulation Analyzer’s AM or FM accuracy. [See
AM Calibration, FM Calibration.]
CALIBRATE and SAVE CAL (Blue Key) enable the Modulation Analyzer to calibrate and save
the resulting calibration factor for either
RF Power, AM, or FM. The CALIBRATE key also
initiates tuned RF level calibration operations. [See AM Calibration, FM Calibration, RF Power.]
CALIBRATION RF POWER OUTPUT makes available a 50 MHz, 1 mW power reference used
to precisely determine the sensitivity of the external power sensor. [See RF Power.]
SET REF (Blue Key) is not a Modulation Analyzer function.
POWER switch applies power
to the Modulation Analyzer when set to ON. [See Instrument
Preset. ]
ZERO causes the Modulation Analyzer to cancel any dc offset that may be present in the power
sensor. [See
RF Power.]
PRE DISPLAY enables FM deviation to be measured before or after de-emphasis. [See FM
De-Emphasis.]
FM DE-EMPHASIS networks equalize pre-emphasized FM. [See FM De-Emphasis.]
HP (High-Pass) and LP (Low-Pass) FILTERS limit the demodulated signal bandwidth. [See
Audio Filters.]
LOCAL returns the Modulation Analyzer to keyboard control from remote (HP-IB) control.
HP-IB Annunciators indicate remote operation status.
3-7