##  [Phase Noise](/phase-noise) 

  ##  [Phase Noise](https://engineering.quantumdictionary.io/phase-noise-0) 

  

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**Engineering & Applied Technologies Dictionary**

 







 

 

 

 



 

 

 

 

Definition

Phase noise is the frequency‑domain spectral density of random, short‑term fluctuations in a carrier signal's phase; commonly reported as single‑sideband phase noise L(f) in dBc/Hz at an offset frequency f from the carrier, representing noise power in a 1 Hz bandwidth relative to the carrier.

 

 

 

 

 





 

 



 ##  [Phase Noise](https://information.quantumdictionary.io/phase-noise-1) 

  

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**Information & Communication Dictionary**

 







 

 

 

 



 

 

 

 

Definition

Random, short‑term fluctuations in the instantaneous phase of an oscillatory carrier signal that produce spectral spreading (noise sidebands) around the nominal frequency and degrade coherent demodulation and adjacent‑channel isolation in communication systems.