Self-Calibrated Multiphase Clock Generation for Low-Noise RF Mixing
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Solution Overview
Problem
Existing multi-phase clock generation devices for RF systems require high-speed clock sources to accurately generate phase-shifted signals, leading to high electric current consumption and noise, especially in applications like harmonic rejection mixers where low-order band-pass filters are insufficient for attenuating unwanted LO harmonics.
Innovation Solution
A multi-phase clock generation device with a self-calibration unit that generates phase-shifted clock signals using a single reference clock, comprising a clock generation unit, phase comparator unit, and self-calibration unit, which determines a delay-calibration parameter to produce multiphase clock signals with reduced current consumption by disabling self-calibration circuitry after initial calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high-speed clock source is used to generate phase-shifted signals, then the phase accuracy is improved, but the electric current consumption increases
Solution Approach 1:
The system performs preliminary calibration of delay elements using a single reference clock to establish accurate phase relationships. Once calibrated, the delay elements are fixed, eliminating the need for continuous high-speed clock operation. This preliminary action enables subsequent low-power operation while maintaining phase accuracy.
Solution Approach 2:
The calibration unit uses the system's own reference clock to calibrate the delay elements, eliminating the need for external high-speed clock sources. The system self-calibrates by comparing phases and adjusting delay elements accordingly, then operates autonomously in low-power mode.
2Measurement precision
If multiple high-speed clock sources are used to generate multiphase signals, then the phase-shift accuracy is improved, but the noise generation increases
Solution Approach 1:
The patent merges multiple clock generation functions into a single reference clock source. By using one reference clock and calibrating delay elements, the system eliminates multiple high-speed clock sources that would otherwise generate noise. The calibrated delay elements then generate the required multiphase signals from this single low-noise reference.
3Stability of the object's composition
If delay elements are continuously calibrated to maintain phase accuracy, then the phase stability is improved, but the electric current consumption increases
Solution Approach 1:
Instead of continuous calibration, the system performs calibration periodically or only when needed (e.g., at power-up or when phase accuracy is required). During normal operation, the calibrated delay elements maintain phase stability without active calibration, significantly reducing power consumption while preserving phase stability.
Data Source
AI summary
Embodiments of a multiphase clock generation device may include an input for feeding a reference clock, a clock generation unit adapted to generate phase-shifted clock signals from the reference clock, and a phase comparator unit functionally coupled with the clock generation unit. The phase comparator unit is adapted to measure a phase shift of the phase-shifted clock signals. The multiphase clock generation device includes a self-calibration unit that is functionally coupled with the clock generation unit. The calibration unit outputs a delay-calibration parameter to the clock generation unit. The clock generation unit is adapted to generate a multiphase clock signal out of the reference clock and the delay-calibration parameter.