N5511A Phase Noise Test System (PNTS)

N5511A Phase Noise Test System (PNTS)

Data Sheets

N5511A PNTS Overview

The Keysight Technologies, Inc. N5511A Phase Noise Test System (PNTS) is a replacement for the “gold-standard” Keysight E5500 phase noise measurement system. PNTS is the foundation of test systems that can measure phase noise down to kT (-177 dBm/Hz at room temperature). This thermal phase noise floor is the theoretical limit for any measurement. Therefore, the PNTS can measure at the limits of physics. Phase noise is unwanted phase modulation noise that emerges from nearly all radio frequency (RF) and microwave devices including oscillators, mixers, frequency dividers, frequency multipliers and amplifiers. PNTS is designed for phase noise “power users” whose needs are consistently unmet by existing commercial phase noise test instrumentation such as “one-box” integrated test solutions. These individuals are typically phase noise experts that would like to fully characterize the phase noise (as well as AM noise and baseband noise) emerging from their radio frequency and microwave devices. Power users, including professionals responsible for developing high-performance aerospace and defense applications as well as characterizing cutting-edge devices for 5G and other wireless communication systems, need to perpetually validate and improve the phase noise performance of their designs.

Frequency range

  • RF input frequency range: 50 kHz to 40 GHz using internal phase detectors
  • Use of external phase detectors allows measurements of millimeter-wave singals to beyond 100 GHz
  • Wide carrier offset range capability, from 0.01 Hz to 160 MHz internally (more than ten decades)

Noise measurement functions

  • Absolute and residual phase noise using the phase detector (quadrature) method in both single channel and two-channel configurations. Two-channels enables use of cross-spectral averaging (cross-correlation) for improving sensitivity down to “kT,” the thermal phase noise floor (-177 dBm/Hz)
  • Measurement of one-port devices (VCO’s, DRO’s, crystal oscillators, synthesizers, etc.) and two–port devices (amplifiers, frequency converters, frequency dividers, etc.), plus CW, pulsed and spurious signals
  • Noise floor (sensitivity) better than -200 dBc/Hz (with +23 dBm and higher input RF signal, using cross-correlation)
  • AM noise on RF carriers from 50 kHz to 40 GHz
  • Baseband noise measurement from 0.01 Hz to 160 MHz
  • Pulsed RF measurements using built-in internal or customer-supplied external PRF filters

Additional capabilities and benefits

  • Designed for phase noise “Power Users” whose needs are consistently unmet by existing commercial phase noise test instrumentation
  • Multi-segment, fast real-time hardware cross-correlation using a Field Programmable Gate Array (FPGA)
  • Replacement for Keysight E5505A with a familiar user interface that is fully SCPI backwards
  • compatible
  • Use of any frequency-tunable source as an external reference which can enable improved sensitivity for single-channel measurements and dramatically reduced cross-correlation time for dual-channel measurements
  • Flexible configurations are possible for a variety of phase noise measurement techniques, including PLL/reference source, residual and FM discriminator methods
  • “Future Proof” with PXIe: add additional pre-qualified modules to complete your test system (e.g. network analyzers, etc.)
  • sets (proprietary closed architectures are less flexible because the embedded reference sources and analyzers can limit phase noise measurement performance)
  • N5510A software enables many standalone instruments to work together within a system
  • Access to external power splitter gives user ability to add external attenuators, amplifiers, and other test setup accessories independently to each channel and suppress any additive noise from these devices via the cross-correlation process.

Keysight N5511A PNTS Theory of Operation

 Phase Detector Technique

The “phase detector with PLL and reference source” technique is the most general-purpose and sensitive measurement approach available for measuring the single sideband (SSB) phase noise characteristic of oscillators (absolute phase noise). This technique removes the carrier and demodulates the phase noise sidebands of the device-under-test (DUT) oscillator. The resulting baseband signal is then digitized and converted into the frequency domain using a Fast-Fourier Transform (FFT) by dedicated baseband analysis hardware. By using the phase detector technique, and thus removing the carrier, one can remove SNR-related limitations of devices in the measurement receiver such as amplifiers and ADCs. Carrier removal can be thought of as raising the ceiling on the ADC full-scale or receiver preamp compression level. As a result, it is possible to optimize system sensitivity by significantly amplifying the detected small-signal baseband phase noise using high-gain baseband amplifiers with low noise figure. This can provide a large improvement in sensitivity compared to other phase noise measurement methods which down-convert the RF carrier to an IF signal and demodulate the phase noise using I-Q demodulation.