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Search Publications by: Dazhen Gu (Fed)

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Displaying 1 - 25 of 142

On Digital Signal Processing of Time Series for Spectrum Estimation

September 11, 2024
Author(s)
Dazhen Gu, Jake Rezac, Xifeng Lu, Dan Kuester
We present a study of power spectral density (PSD) estimation from data sampled in the time domain. This work was motivated by our recent development of digital radiometry, where radiation spectra were obtained by processing the digitally sampled signal

CHARACTERIZATION OF MICROWAVE BLACKBODY WITH MONOSTATIC MEASUREMENT

September 5, 2024
Author(s)
Dazhen Gu, Jonah Smith, Adam Whitney, Omar Khatib, Natalie Rozman, Amanda Gregg, Willie Padilla, William Deal, Steven Reising
This paper describes a characterization method for measuring the reflectivity of blackbodies used as calibration devices in spaceborne instruments. The fundamental measurement principle is based on the scattering matrix theory. A monostatic apparatus has

Radio Spectrum Occupancy Measurements Amid COVID-19 Telework and Telehealth

October 14, 2022
Author(s)
Dan Kuester, Xifeng Lu, Dazhen Gu, Azizollah Kord, Jake Rezac, Katie Carson, Marla L. Dowell, Elizabeth Eyeson, Ari Feldman, Keith Forsyth, Vu Le, John Marts, Mike McNulty, Kyle Neubarth, Andre Rosete, Matthew Ryan, Maija Teraslina
During the COVID-19 pandemic, NIST began a targeted campaign of measurements of averaged power and occupancy rate in the radio spectrum. The purpose was to sample real environments to offer timely insights into data infrastructure where it might be

Measurements of IP3 and P1dB for Spectrum Monitoring with Software Defined Radios

March 30, 2022
Author(s)
Mike McNulty, Dazhen Gu, Dan Kuester, Payam Nayeri
This paper discusses methodology for characterizing linearity summary parameters of software-defined radio receivers. First, we introduce a highly automated testbed for 1-dB compression point (P1dB) and third-order input intercept point (IIP3). With this

DEVELOPMENT OF NbN TERAHERTZ HEB MIXERS COUPLED THROUGH SLOT-RING ANTENNAS.

October 12, 2021
Author(s)
Eyal Gerecht, Dazhen Gu, Xin Zhao, John Nicholson, Fernando R. Morales, Sigfrid Yngvessen
In order to improve the power coupling to Phonon-Cooled Hot Electron Bolometric (PHEB)devices, we are experimenting with a different type of antenna. The goal of the project is to eliminate the need for a beam splitter or diplexer and to couple both the

Measurement Challenges for Spectrum Sensing in Communication Networks

April 27, 2021
Author(s)
Dan Kuester, Yao Ma, Dazhen Gu, Adam Wunderlich, Jason Coder, Joseph R. Mruk
We summarize a few key spectrum sensing measurement challenges and recent advances. Laboratory tests of sensing are complicated by their inseparable and often imbedded role in modern hardware. Results are difficult to calibrate because physical parameters

Noise Influence on Scattering-Parameter Measurements

November 4, 2020
Author(s)
Dazhen Gu, Jeffrey A. Jargon, Matthew J. Ryan, Anouk Hubrechsen
We present a general model of noise-influenced scattering (S) parameter measurements performed by a vector network analyzer (VNA). The residual error of the S-parameter due to the noise appears like a complex Gaussian quotient. The statistical analysis of

Digital Radiometer for Traceable Spectrum Sensing

September 14, 2020
Author(s)
Xifeng Lu, Dazhen Gu, Daniel G. Kuester
This paper describes a metrology instrument designed for detecting noise and interference in digital communications. A quadrature detector downconverts in-phase (I) and quadrature (Q) channels, which are each digitized at high speed. This architecture

Blind Measurement of Receiver System Noise

June 4, 2020
Author(s)
Dan Kuester, Adam Wunderlich, Duncan McGillivray, Dazhen Gu, Audrey Puls
Tightly packaged receive systems pose a challenge for noise measurements. The only available receiver outputs are often user data: link benchmark or diagnostic information that can be scavenged with software. These could include data rate benchmark, self