Shared Oscillator Signal Conditioning for Phase Noise Correlation

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Solution Overview

Problem

In multi-stage signal processing circuits, independent oscillators lead to uncorrelated phase fluctuations, resulting in increased noise due to the lack of correlation among the oscillators and clock generators at each stage, which deteriorates the signal-to-noise ratio.

Innovation Solution

Implementing a single common oscillator across all stages of the circuit, including the digital/analog converter, I/Q modulator, and mixers, to correlate phase fluctuations and reduce overall noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple independent oscillators are used for each stage, then each stage can operate independently, but the phase fluctuations become uncorrelated and overall noise increases

Engineering Contradiction:
Improveindependent operation of each stageVSAvoidoverall noise
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent merges multiple independent oscillators into a single common oscillator that serves all signal processing stages. This common oscillator generates a master clock signal that is distributed to all stages, ensuring correlated phase fluctuations and reduced overall noise while maintaining independent functional operation of each stage through the use of the shared clock signal.

Inventive Principle:
Principle #5Merging (Combining)

2Object-affected harmful factors

If a single common oscillator is used across all stages, then phase fluctuations are correlated and overall noise decreases, but the circuit complexity increases

Engineering Contradiction:
Improveoverall noiseVSAvoidcircuit structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The common oscillator is designed to serve multiple functions across different signal processing stages simultaneously. A single oscillator circuit generates the master clock signal that is universally distributed to the digital/analog converter, I/Q modulator, and all mixer stages, eliminating the need for multiple separate oscillator circuits while maintaining correlated phase behavior throughout the system.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP1946438B1Signal conditioning circuit with a shared oscillator
Publication Date: 2013.07.31 ROHDE & SCHWARZ GMBH & CO KG
  • EP1946438B1 patent drawingFigure 1
  • EP1946438B1 patent drawingFigure 2
  • EP1946438B1 patent drawingFigure 3~4

AI summary

The invention relates to a signal conditioning circuit with a digital/analog converter (1), an I/Q modulator (2) and at least one mixer (3, 4). According to the invention, instead of a multiplicity of oscillators for the individual stages (21-24), a single oscillator (16) is used. The total noise of the stages (21-24) is decreased by the resulting correlation.