Quadrature Modulator Phase Correction Circuit
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Solution Overview
Problem
Existing wireless communication systems face challenges in maintaining accurate phase relationships and matching amplitudes between in-phase and quadrature local oscillator (LO) signals, leading to intermodulation distortion and performance degradation in quadrature modulation and demodulation processes.
Innovation Solution
The implementation of a quadrature modulator with phase-detection and correction circuitry, including phase-detect mixers and phase-correction mixers, to accurately align the phase difference between in-phase and quadrature LO signals to 90 degrees and adjust their amplitudes to match, using a quadrature hybrid or phase-splitting circuitry, ensuring accurate phase and amplitude correction over a large frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If quadrature modulation and demodulation are implemented, then data rates and bandwidth efficiency are improved, but phase errors between in-phase and quadrature LO signals cause intermodulation distortion and performance degradation
Solution Approach 1:
The patent implements a feedback mechanism where phase-detection circuitry continuously monitors the phase relationship between in-phase and quadrature LO signals and generates correction signals to adjust the phase, ensuring accurate quadrature modulation and demodulation while maintaining high data rates
Solution Approach 2:
The patent dynamically adjusts phase and amplitude parameters of LO signals using phase-correction circuitry and amplitude-correction circuitry to maintain optimal signal characteristics across varying operating conditions and frequency ranges
2Productivity
If quadrature modulation and demodulation are implemented, then bandwidth efficiency is improved, but amplitude mismatches between in-phase and quadrature LO signals lead to output signal mismatches
Solution Approach 1:
The patent employs feedback through amplitude-detection circuitry that monitors amplitude levels of in-phase and quadrature LO signals and generates correction signals to equalize amplitudes, ensuring consistent output signal quality while maintaining bandwidth efficiency
Solution Approach 2:
The patent dynamically adjusts amplitude parameters using amplitude-correction circuitry to compensate for mismatches between in-phase and quadrature LO signals, maintaining precise amplitude matching across different operating conditions
3Measurement precision
If phase and amplitude correction circuitry are added to quadrature modulator, then phase alignment and amplitude matching are improved, but device complexity increases
Solution Approach 1:
The patent combines phase-detection, phase-correction, amplitude-detection, and amplitude-correction functions into an integrated correction system within the quadrature modulator, achieving precise phase and amplitude matching while minimizing the increase in device complexity through functional integration
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution ensures accurate phase alignment and amplitude matching of LO signals, reducing intermodulation distortion and enhancing the performance of wireless communication systems by maintaining optimal signal integrity and efficiency across various frequency ranges.
Implementation Method 1
The quadrature modulator can include a quadrature hybrid to receive an LO signal from a phase-locked loop or other clock source. The quadrature hybrid can provide in-phase and quadrature components of the LO signal
Implementation Method 2
The phase-detect mixer can be coupled to modulate the amplitude-and-phase-corrected LO signals to provide a phase-correction signal. The phase-correction signal can have an amplitude proportional to a deviation in phase from 90 degrees
Implementation Method 3
The first phase-correction mixer can modulate the phase-correction signal with the quadrature LO signal from the quadrature hybrid to generate an output that is then summed by a first summing circuit with the in-phase LO signal from the quadrature hybrid
Data Source
AI summary
Circuits, methods, and apparatus that can provide in-phase and quadrature LO signals having an accurate phase relationship and matching amplitudes. An example can provide a quadrature modulator having phase-correction circuitry and amplitude-correction circuitry. The quadrature modulator can include a quadrature hybrid to receive an LO signal from a phase-locked loop or other clock source. The quadrature hybrid can provide in-phase and quadrature LO signals to phase-correction circuitry, which can accurately align a difference in the phase of the in-phase and quadrature signals to 90 degrees. The amplitudes of the resulting signals can be adjusted to have a desired amplitude using amplitude-correction circuitry. The amplitude-and-phase-corrected LO signals can be used to modulate in-phase and quadrature components of a baseband signal. The modulated products can be combined, gained, and filtered as necessary for wireless transmission, device testing, or other purpose.