Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Thermal Noise Metrology with Time-Based Synthesis



Dazhen Gu


We present a new measurement technique of quantifying noise temperature based on temperature and time. A single pole double throw (SPDT) ultra-fast switch combines signal from outputs of two synchronized electromechanical (EM) switches. The input ports of EM switches are terminated by one unknown noise source, one known cold noise source, and two known noise references at ambient temperature. The magnitude of the combined noise signal can be adjusted by the duty cycle of the transistor-transistor logic (TTL) pulse that controls the fast switch. The measurement approaches the balanced mode by regulating the TTL duty cycle in order to minimize the difference between the combined noise signal and the ambient noise reference. In comparison to conventional total-power radiometers, this new instrumentation is more efficient and potentially provides a wider dynamic range.
Proceedings Title
Conference on Precision Electromagnetic Measurements
Conference Dates
July 8-13, 2018
Conference Location
Paris, FR


Balanced radiometer, feed-back loop, noise synthesis, switch, thermal noise.


Gu, D. (2018), Thermal Noise Metrology with Time-Based Synthesis, Conference on Precision Electromagnetic Measurements, Paris, FR, [online], (Accessed May 28, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created July 8, 2018, Updated April 11, 2022