I/Q Local Oscillator Generation With Low Phase Mismatch
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Solution Overview
Problem
Conventional methods for generating in-phase (I) and quadrature-phase (Q) local oscillator signals suffer from amplitude and phase mismatch, especially at high frequency ranges like 30-80 GHz, leading to performance issues and increased power consumption.
Innovation Solution
A method and device for generating I and Q signals by receiving two signals of the same frequency with different phase angles, adding and subtracting these signals to produce sum and difference signals, and adjusting the amplitude of these signals to reduce mismatch, thereby providing orthogonal I and Q signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If poly-phase filters are used to generate 90-degree phase shift, then I and Q signals are generated, but amplitude and phase mismatch occurs and bandwidth is limited
Solution Approach 1:
The patent changes the operating parameters by using a single-phase signal with programmable phase shift and amplitude control, replacing the fixed poly-phase filter architecture. This allows dynamic adjustment of phase and amplitude parameters to maintain accuracy across wide frequency ranges (30-80 GHz), resolving the contradiction between phase precision and frequency adaptability.
2Speed
If clock dividers are used to generate I and Q signals, then frequency division is achieved, but additional jitter and phase noise are introduced
Solution Approach 1:
The patent extracts and eliminates the clock divider stage from the signal generation path. By directly generating I and Q signals through programmable phase shifting and amplitude modulation of a single-phase source, the harmful jitter and phase noise introduced by frequency division are completely removed, while still achieving the required frequency synthesis.
3Speed
If higher frequency LO generation (4×VCO) is implemented, then I and Q components are generated, but power consumption increases and implementation becomes difficult at high frequencies
Solution Approach 1:
Instead of the conventional approach of generating high-frequency LO signals and then dividing them down (4×VCO method), the patent inverts the approach by generating baseband I and Q signals directly through programmable phase shifting, then modulating them to the desired frequency. This eliminates the need for high-frequency VCO operation and associated power consumption.
4Ease of manufacture
If analog circuits are used to generate I and Q components, then LO signals are produced, but amplitude and phase mismatch is introduced
Solution Approach 1:
The patent incorporates feedback mechanisms through programmable control that continuously monitors and adjusts phase and amplitude parameters. This closed-loop control compensates for analog circuit variations and mismatches, ensuring precise I and Q signal generation despite manufacturing tolerances in the analog components.
Data Source
AI summary
According to an aspect, a method of generating an In-phase (I) and a Quadrature phase (Q) signal in an electronic system comprises receiving a first signal and a second signal of same frequency with different phase angle, adding the first and the second signal to generate a sum signal that is sum of the first and the second signal, subtracting the first signal from the second signal to generate a difference signal that is difference of the first and the second signal and providing the sum signal and the difference signal as the I signal and Q signal.