Multiphase LO Signal Generation Using Delay and Phase Interpolation
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Solution Overview
Problem
Generating multiple phases of local oscillator signals for quadrature amplitude modulation in wireless communication devices results in excessive noise and power consumption, particularly when using ring oscillators or dividers, which are not suitable for cellular applications.
Innovation Solution
The implementation of multiphase signal generation circuitry that uses delay circuitries and phase interpolators to generate output signals out-of-phase by half of the quadrature delay, avoiding the use of ring oscillators, dividers, and delay-locked loop circuitry, and operating in an open-loop configuration to reduce noise and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ring oscillators or dividers are used to generate multiple phases of local oscillator signals, then the signal generation function is achieved, but excessive noise and power consumption occur
Solution Approach 1:
The patent changes the fundamental operating parameters by using delay circuitries with adjustable delay amounts instead of fixed-frequency ring oscillators. By controlling the delay amount of each delay circuitry, the system generates multiple phase signals (e.g., 0°, 45°, 90°, 135°) with reduced power consumption and noise compared to traditional ring oscillator-based approaches.
2Reliability
If ring oscillators or dividers are used to generate multiple phases of local oscillator signals, then the signal generation function is achieved, but excessive noise is produced
Solution Approach 1:
The patent changes the fundamental operating parameters by using delay circuitries with adjustable delay amounts instead of fixed-frequency ring oscillators. By controlling the delay amount of each delay circuitry, the system generates multiple phase signals (e.g., 0°, 45°, 90°, 135°) with reduced power consumption and noise compared to traditional ring oscillator-based approaches.
3Measurement precision
If delay-locked loop circuitry is used to generate multiple phases, then phase accuracy is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent segments the phase generation function into multiple independent delay circuitries, where each delay circuitry contributes a specific delay amount. By combining these segmented delay elements in parallel configurations, the system achieves accurate phase control without requiring complex delay-locked loop circuitry, thereby reducing overall device complexity.
Solution Approach 2:
The delay circuitries are designed to be multi-functional, serving both as phase shift elements and as controllable delay elements. This universal design allows the same delay circuitry components to generate multiple phase signals simultaneously, eliminating the need for separate dedicated circuitry for each phase, thus reducing overall system complexity.
Data Source
AI summary
Multiphase signal generation circuitry receives input signals that are out-of-phase with one another by a quadrature delay (e.g., 90°), and generates output signals that are out-of-phase with one another by half of the quadrature delay. A first input signal may be provided to a first delay circuitry, which is then input to a first phase interpolator. The first delay circuitry is also input to second delay circuitry, which also generates an output that is input to the first phase interpolator. The first phase interpolator outputs a first output signal. The second delay circuitry is input to third delay circuitry, which in turn is input to a second phase interpolator with a second input signal that is out-of-phase with the first input signal by the quadrature delay. The second phase interpolator outputs a second output signal that is out-of-phase with the first output signal by the half of the quadrature delay.