Keysight (Agilent) N5511A Phase Noise Test System

The Keysight (Agilent) N5511A Phase Noise Test System is a dedicated measurement platform for characterizing phase noise across oscillators, synthesizers, and broadband signal sources. It succeeds the E5500 and delivers sensitivity to the theoretical thermal noise floor - kT at −177 dBm/Hz - making it the instrument of choice for phase noise power users requiring measurements at the limits of physics. The system performs absolute phase noise, AM noise, residual noise, baseband noise, and pulsed RF measurements on both one-port devices (VCOs, DROs, crystal oscillators, synthesizers) and two-port devices (amplifiers, frequency converters, frequency dividers).

Fast cross-spectral averaging using FPGA-based real-time hardware cross-correlation delivers sensitivity better than −200 dBc/Hz with +23 dBm input RF signal.

Technical Specifications

• RF input: 50 kHz to 40 GHz (internal phase detectors)


• Millimeter-wave: beyond 100 GHz (external phase detectors)


• Optional: 3 GHz and 26.5 GHz variants Offset Frequency Range


• Internal: 0.01 Hz to 160 MHz


• Extended range via external signal analyzer Phase Noise Sensitivity


• Cross-correlation (Xcorr): better than −200 dBc/Hz at +23 dBm RF input


• Absolute phase noise: −153 dBc/Hz (10 GHz @ 10 kHz offset, Xcorr=1)


• Residual phase noise: −187 dBc/Hz (10 GHz @ 10 kHz offset, Xcorr=1)


• Noise floor: −177 dBm/Hz (room temperature thermal limit) Measurement Capability


• CW and pulsed RF modes


• High dynamic range architecture


• Phase detector (quadrature) method with cross-spectral averaging

Key Features

• Modular PXIe mainframe, 4U height


• Integrated PC controller, Windows 10


• Phase detector and data conversion modules


• Multi-segment FPGA-based hardware cross-correlation


• SCPI backwards compatible


• All N5510A application software features included

Typical Applications Characterization of spectral purity in oscillators and synthesizers for R&D and production environments. Residual noise measurements of low-noise amplifiers and frequency conversion devices.

Compatibility & Integration Flexible, scalable architecture accommodates external reference sources. Requires external monitor, keyboard, and mouse. AC power cord included.