HP 8901B Modulation Analyzer
150 kHz - 1300 MHz
HP 11722A Sensor Module
100 kHz - 2600 MHz
Technical Specifications
• RF Power: ±0.02 dB
instrumentation accuracy
• RF Frequency: 10 Hz resolution
• AM and FM: 1% accuracy
Four Instruments In One
• fM: 3% accuracy
• Audio Characterization
AC Volts: ±4% accuracy
Frequency: 6 digits of resolution
Distortion: ±1 dB accuracy
The HP 8901B Modulation Analyzer combines four
precise measurement functions into one fully
automatic, HP-IB programmable instrument. It includes
a power meter, modulation analyzer, frequency counter,
and audio analyzer. For precise signal analysis, the
HP 8901B Modulation Analyzer provides the
performance you need, the features you want, and the reliability and serviceability you expect.
RF Power delivers the accuracy and resolution of a
high performance power meter. The HP 8901B with the
HP 11722A Sensor Module measures power from
+30 dBm to – 20 dBm at frequencies from 100 kHz
to 2.6 GHz. The HP 8901B accepts all HP 8480 series
power sensors for extended measurement
capability.
AM and FM measurements offer 1% accuracy
(3% accuracy for φM) and fast one-key operation. The
HP 8901B has extremely low internal noise, and very
low AM/φM and φM/AM conversion, for accurately
measuring residual and incidental AM, FM and φM on
a wide range of simple and complex modulated signals.
RF Frequency of complex modulated signals can be
difficult to measure, but not with the HP 8901B.
Automatically tuning to the largest input signal or to any
user specified frequency, the HP 8901B counts with
10 Hz resolution.
Audio distortion, frequency and level measurements
provide comprehensive characterization of the modulation signal.
HP 8901B Modulation Analyzer and
HP 11722A Sensor Module
In Track Mode, the Analyzer continuously tracks a swept signal. Range Hold
freezes the instrument settings at their current value.
Indicators display current HP-IB
Independently selectable
high-pass and low-pass
filters match the post-detection
bandwidth to the application.
Four standard de-emphasis
networks are available for FM
measurements. Using the
Pre-display key, the de-emphasis
networks are positioned before
the displayed measurement
circuit, to display “de-emphasized”
FM deviation.
STATUS.
Large 10- digit LED display for all
measured results and error
messages.
Store and recall instrument
settings in eight non-volatile
memory locations.
Enter RF Power calibration factors
into non-volatile memory for
automatic compensation of power
sensor efficiency and mismatch loss.
This connector has
two functions. It serves
as a recovered
modulation output for
external measurements,
or external audio input
for ac level, frequency
or distortion
measurements.
Zero the HP 11722A Sensor
Module without removing
it from the device
under test.
Accurate 1mW reference
for RF power calibration.
AM/FM calibrator provides
extremely accurate signals for
modulation calibration. AM
depth and FM deviation are
calibrated to 0.1% accuracy.
Recorder output provides a dc voltage proportional to the
measured result.
Modulation detector keys
select positive peak, negative
peak, ±peak/2, average, or
rms detectors. Peak Hold is
used with either peak detector
for measuring transients.
Selectable formats
display results in the
units desired.
Pull-out information
cards for quick reference
to instrument operation,
special functions, and
error messages.
Special function key for
complete control of
Analyzerfunctions. This key also
executes many built-in
troubleshooting routines.
The Analyzer
automatically
recognizes which
power sensor is used
and sets the appropriate
power ranges.
If using the HP 8901B
without the HP 11722A,
input circuitry is
protected from damage
for signals up to
25 watts.
Remote control output for user configured power
sensor/receiver input switch.
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TTL level indicates Frequency Offset Mode.
HP-IB: Not just lEEE-488, but the hardware,
documentation and support that delivers the
shortest path to a measurement system.
With the HP 11722A Sensor Module, all
measurements including RF Power are made at
a single connector.
For Your Applications
Transmitter Testing
You can perform your standard transmitter measurements with the HP 8901B Modulation Analyzer. It measures transmitter output power very accurately, and it
counts frequency to 10 Hz resolution. The HP 8901B
will accurately measure the signal modulation, and
characterize the demodulated audio signal’s frequency,
level and distortion.
The HP 8901B includes many features designed for
transmitter testing, such as a Peak Hold detector for
capturing short transient modulation signals and a special Tone-Burst-Receiver Mode. Using this mode, audio
signals are captured and demodulated in <5 msec. This
is used for demodulating signalling tones sent when a
transmitter is first keyed. Because the HP 8901B may
be directly connected to the output of the transmitter,
overpower protection to 25 watts is standard.
RF Signal Characterization
The HP 8901B Modulation Analyzer is an excellent lab
and production tool for accurately characterizing RF
signals from 150 kHz to 1300 MHz.
The HP 8901B’s built-in power meter eliminates the
need for an external power meter. Unlike diode detectors, the HP 8901B’s power meter accurately measures
signals with harmonics and spurious.
Use the HP 8901B to perform residual AM and FM measurements of such low noise sources as crystal oscilla-
tors, or make accurate AM/φM and AM/AM conversion
measurements of phase and amplitude sensitive devices such as bandpass filters and multiple channel receivers. Excellent isolation between AM and FM makes
it simple to separate the AM and φM of AM stereo, incidental AM of FM transmitters and the AM, FM and φM
components of complex signals.
Automatic Test Systems
The HP 8901B is an important component of automatic
RF test systems. All functions – power measurement,
frequency count, modulation, and audio analysis – are
fully automatic and easily programmed. With these
measurements combined into one instrument, interfacing requirements, hardware costs, and software development time are reduced.
Because of its precision modulation and power measurements, the HP 8901B is a valuable tool for calibrating automatic test systems.
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Performance You Need
RF Power: Power Meter Accuracy
The HP 8901B Modulation Analyzer performs power
measurements with superb accuracy and measurement
ease. Power meter linearity is ±0.02 dB plus ±0.02 dB
per range change. With a single key stroke the
HP 8901B automatically senses the power sensor type,
autoranges to the input signal, measures its power,
compensates for sensor flatness, and displays the results in units you choose. In addition to the
HP 11722A Sensor Module, the HP 8901B accepts all
HP 8480 series power sensors for power measurements
from -70 dBm (100 pW) to +44 dBm (25W) at frequencies from 100 kHz to 26.5 GHz.
If you change sensors, just enter the new calibration
factors into non-volatile memory, either from the keyboard or via HP-IB. You can store two complete sets of
sensor calibration factors.
The front panel Power Reference enables precise calibration of your power sensor at the reference calibration factor frequency. This 50 MHz reference is set to
1.00 mW ±0.7%, traceable to the U.S. National Bureau
of Standards.
AM, FM and fM: Superb Accuracy
Precise AM, FM, and φM measurements are a major
contribution of the HP 8901B Modulation Analyzer. Basic measurement accuracy is 1% for AM and FM and 3%
for φM. With excellent separation between the FM dis-
criminator and AM detector, incidental AM and FM
measurements are made easily and accurately.
Residual AM in a 50 Hz to 3 kHz bandwidth is less than
0.01%. The very low noise FM discriminator makes re-
sidual FM measurements of less than 1 Hz at 100 MHz
increasing linearly with frequency to less than 8 Hz at
1300 MHz.
RF Power and AM/FM calibrators
RF Frequency: High Resolution
The HP 8901B Modulation Analyzer counts all types of
modulated signals with 10 Hz resolution. The high stability reference option has an aging rate of less than
1X10-9/day. For selectively counting low level signals,
use the HP 8901B’s manual tune mode.
Audio: Built-in Convenience
The HP 8901B’s audio capabilities often eliminate the
need for external equipment when measuring demodulated signals or external audio signals. The Analyzer
counts audio frequencies with 6 digits of resolution,
measures distortion of 400 Hz and 1000 Hz signals and
measures rms levels from 100 mV to 3V with
4% accuracy.
Select from six detectors for modulation measurements. In addition to positive and negative peak detectors, the HP 8901B provides a ±Peak/2 detector, For residual noise measurements, choose from an average
responding detector which is rms sinewave calibrated
or a true rms detector. The Peak Hold detector captures and holds the maximum positive or negative peak
modulation of a signal. This is ideal for modulation limiting tests.
The AM/FM calibrator provides extremely accurate
modulated signals with ±0.1% accuracy, for easy selfcheck and re-calibration of the instrument AM and FM
calibration factors.
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