The Agilent 8901B Modulation Analyzer is a fully automatic, GPIB-programmable instrument that combines four precise measurement functions — power meter, modulation analyzer, frequency counter, and audio analyzer — into a single chassis covering 150 kHz to 1300 MHz. Paired with the 11722A Sensor Module, the system extends RF power measurement to 100 kHz–2.6 GHz, and the 8901B also accepts the full 8480 series power sensors for power measurements from -70 dBm to +44 dBm at frequencies up to 26.5 GHz. Operation is single-key automatic: select the measurement and the analyzer tunes to the largest input signal, autoranges, and displays the result in user-selectable units.

The 8901B is built for three primary application areas the manufacturer documents on the datasheet: transmitter testing, RF signal characterization, and automatic test systems. For transmitter work, the analyzer measures output power, counts carrier frequency to 10 Hz resolution, characterizes modulation, and analyzes the demodulated audio for frequency, level, and distortion — with a Peak Hold detector for capturing transient modulation events and a Tone-Burst-Receiver mode that demodulates signaling tones in under 5 ms. For RF signal characterization, the built-in power meter, low-noise FM discriminator, and excellent AM/FM separation support residual AM and FM measurements on crystal oscillators as well as AM/φM and AM/AM conversion measurements on filters and multi-channel receivers. In automatic test systems, all four functions are programmable through one GPIB interface, consolidating hardware and reducing integration effort.

ValueTronics International maintains a deep inventory of professional test and measurement equipment — including the 8901B and 11722A family — at our 20,000 square-foot secure warehouse at 1675 Cambridge Drive in Elgin, Illinois. Equipment is received, inspected, performance-verified, and tested in-house by our technicians before it ships, providing a level of accountability and documentation that pass-through brokers and drop-shippers cannot match. When you order the 8901B or the 11722A Sensor Module from ValueTronics, the instrument has been through our process, not just transferred from one address to another.

Brand Heritage

The 8901B carries the lineage of Hewlett-Packard's test and measurement business. HP spun out its T&M division as Agilent Technologies in 1999, and Agilent later transferred the electronic measurement business to Keysight Technologies in 2014. Instruments originally marketed under HP that continued through the Agilent era — including this analyzer — share design and calibration heritage with the current Keysight catalog, even though the 8901B itself is no longer in active production.

Compare Other Models in This Series

The 8901B is a single-model instrument rather than a tiered family. Its companion is the 11722A Sensor Module, which is also available as Option 021 bundled with the analyzer. The 8901B accepts the full 8480-series power sensors (8481A/1B/1H, 8482A/2B/2H, 8483A, 8484A, 8485A) for power measurement coverage that the 11722A alone does not provide — extending range to -70 dBm and frequency coverage to 26.5 GHz on selected sensors.

Beyond the sensor pairing, the 8901B's configuration choices are option-driven rather than model-driven: rear-panel I/O (Option 001), high-stability 1×10⁻⁹/day reference oscillator (Option 002), external LO operation (Option 003), 48–400 Hz line operation (Option 004), and the high-selectivity carrier-noise option group (Options 030–037) that adds 12.5 kHz, 25 kHz, 30 kHz, and 2 kHz carrier-noise filters for cellular and adjacent-channel measurements.

Each pre-owned 8901B and 11722A available through ValueTronics is offered on its own product page with condition-matched pricing. Option content (rear-panel I/O, high-stability reference, carrier-noise filters) varies unit by unit; confirm the option string on the specific instrument before ordering to ensure it matches your application.

The 8901B's combination of four instruments in one chassis, ±0.02 dB power linearity, 1% AM/FM accuracy, 10 Hz frequency resolution, and the 11722A single-connector power-plus-modulation interface defines the unit's place in legacy RF metrology benches. Its frequency-offset mode is the feature that extends its useful life well past the 1300 MHz native ceiling and keeps it relevant in microwave production test systems built around it.

The principal configuration distinction is between the base 8901B (front-panel I/O) and Option 001 (rear-panel I/O for rack and ATE integration). The high-stability Option 002 reference oscillator (1×10⁻⁹/day aging) is the upgrade path for customers whose frequency accuracy requirements exceed the standard 1×10⁻⁶/month reference.

The Options 030–037 group converts the 8901B into a high-selectivity carrier-noise measurement platform, adding adjacent-channel and alternate-channel filters required for cellular and land-mobile carrier-noise measurements. Option 030 requires rear-panel external LO connections and is mutually exclusive with the 8902A Option 003 rear-panel LO configuration; see the option matrix above the comparison table for the specific filter selections (032, 033, 035, 037).

Additional differences in specifications beyond the few shown above are not listed here — see each model's full specifications below.

Product Core & Specifications

About this used unit

• Warranty included
• Functional verification included
• Standard Calibration Upgrade Options: No Calibration Required, NIST Traceable, Z540.1 or ISO 17025 with Data, Z540.3 Guardbanding with Data.
• Note that unnecessary accessories may not be included (contact Test Architect to confirm).

Please review the Manufacturer's Data Sheet to verify published specifications. Feedback on this webpage is always welcome — please reach out to your Test Architect at any time for questions or concerns. Thank you, we truly appreciate you being our customer.