Phase noise is an unwanted phase modulation noise that emerges in nearly all radio frequency and microwave devices including oscillators, mixers, dividers, multipliers and amplifiers. Power users, including professionals responsible for developing high-performance aerospace and defense applications as well as cutting-edge device characterization for 5G and other wireless communication systems, need to validate the phase noise performance of their designs.
The Keysight N5511A PNTS is a replacement for the gold-standard Keysight E5500 phase noise measurement system. PNTS is designed for phase noise “Power Users” at the high-end of the market. These are phase noise experts that would like to fully characterize the phase noise (and AM noise and baseband noise) emerging from their radio frequency and microwave devices.
Keysight's new N5511A Phase Noise Test System (PNTS) models are available in three frequency ranges - from 50 kHz and going up to 3, 26.5, or 40 GHz with offsets from .01 Hz to 160 MHz internally. All can be configured for either single or dual-channel operation and feature a flexible architecture for easy integration of external reference sources enabling users to select from a variety of commercially-available low-noise sources.
The phase detector (quadrature) technique maximizes dynamic range, supporting best-in-class absolute and residual measurements on both continuous wave and pulsed signals, and cross spectral averaging (cross-correlation) to measure noise approaching the limits of physics, down to the kT (–177 dBm/Hz) thermal noise floor, by removing uncorrelated noise between two channels and enabling users to see the real performance of their device under test.
"In terms of radio frequency and microwave design, less phase noise means more performance, and the new Keysight N5511A PNTS can help customers achieve that performance," says Dan Dunn, vice president and general manager of Keysight's Aerospace Defense and Government Solutions Group. "Its flexible architecture lets customers integrate exceptional reference sources – theirs or ours – and confidently solve specific challenges faster."
The N5511A’s flexible architecture allows users to integrate exceptional reference sources and solve specific challenges faster. PNTS can accept any reference source that is electronically frequency tunable. This allows the use of the best available signal generators today (or even use copies of the DUT as references) and get better performance down the road as newer and higher performance signal generators come to market. The user can start out with reference performance equal to or better than their device and add to test margin with the cross-correlation process.
PNTS performs multi-segment hardware cross-correlation in a Field Programmable Gate Array (FPGA). This means the PNTS suppresses excess noise from the system itself or from reference sources and test accessories (amplifiers, attenuators etc.) through a computational process called cross-spectral averaging, or cross-correlation. This is done in FPGA hardware, rather than in software on a microprocessor (CPU) and is therefore much faster. The computations are performed on all segments of the trace in parallel and display this in real time on the display.
Beyond speed of measurement (with exceptional references and hardware cross-correlation), the PNTS is also extremely flexible. It can measure many types of noise (AM noise, baseband noise, pulsed, residual and absolute phase noise) and accept many different test accessories. The system gives access to both channels via an external power splitter - allowing the user to add test accessories for signal conditioning (i.e. amplifiers and attenuators) to each channel independently. This enables the N5511A PNTS to suppress any additive noise from these test accessories with cross-correlation. This allows the user to see only the true performance of their device on the system display.
The N5511A is available now and consists of phase detector and data conversion modules housed in a custom, low-noise single PXIe mainframe four units (4U) high. The system software included runs on an integrated PC controller using the Microsoft Windows 10 operating system. Prices start at USD $135,000.