RF Phase Noise Extraction Using Complementary Autocorrelation
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Solution Overview
Problem
Existing phase noise measurement techniques cannot distinguish or accurately measure pure phase noise induced by transmitters on RF signals, as it is masked by other types of phase noise from complex sources such as thermal noise and modulation-induced noise.
Innovation Solution
A method and apparatus that digitize RF signals, remove modulation and suppress carriers to isolate phase noise, apply complementary autocorrelation to attenuate secondary noise, and represent the power spectrum of phase noise, allowing for separate measurement of pure phase noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing phase noise measurement techniques are used, then an aggregate measurement of phase noise is obtained, but pure phase noise cannot be distinguished from other sources of noise
Solution Approach 1:
The patent segments the aggregate phase noise measurement into distinct components by applying complementary autocorrelation processing. This separates pure phase noise from other noise sources (thermal noise, modulation-induced noise, synchronization-induced noise) that were previously indistinguishable in the aggregate measurement
Solution Approach 2:
The patent extracts pure phase noise from the composite noise signal by using complementary autocorrelation to isolate and remove contributions from other noise sources. This extraction process retrieves only the pure phase noise component induced by transmitter oscillators
2Measurement precision
If existing measurement techniques are used, then measurement simplicity is maintained, but the ability to separately measure pure phase noise is lost
Solution Approach 1:
The patent replaces complex hardware-based separation techniques with signal processing methods. By using complementary autocorrelation algorithms applied to digitized RF signals, the system achieves noise source separation without requiring complex physical measurement setups
3Measurement precision
If aggregate phase noise measurement is performed, then measurement coverage is comprehensive, but measurement specificity for pure phase noise is reduced
Solution Approach 1:
The patent introduces complementary autocorrelation as an intermediary processing step between signal acquisition and phase noise measurement. This intermediary operation selectively attenuates certain noise components while preserving pure phase noise, enabling specific measurement of the desired parameter
Data Source
AI summary
A phase noise extraction apparatus and technique that extracts phase noise induced by a component of a transmitter from a radio frequency (RF) signal and attenuates noise induced from other sources. The RF signal is digitized, modulation is removed, and the carrier is suppressed to provide a noise signal including the phase noise and the noise induced from the other sources. A complementary autocorrelation operation is applied to the noise signal to attenuate the noise from the other sources. The correlated signal is transformed into the frequency domain to generate a power spectrum of the phase noise that may be measured or displayed.