Wide-Tuning LO Generator Architecture for Harmonic Isolation
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Solution Overview
Problem
Traditional local oscillator (LO) generator schemes face corruption from power amplifier feedback and spurious harmonics, leading to inefficiencies and increased power consumption, especially when using non-linear power amplifiers or generating signals close to harmonic frequencies.
Innovation Solution
A wide tuning range oscillator-based LO generator system that uses frequency dividers and a frequency combiner to generate a final frequency separated by at least a factor of two from the initial frequency, avoiding harmonic relationships and reducing power consumption by eliminating the need for mixers in some modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a frequency divider with factor K is used to separate LO frequency from PA output frequency, then feedback corruption is avoided, but Kth harmonic of PA output can still corrupt LO generator output through RF coupling paths
Solution Approach 1:
The patent changes the frequency parameter relationship by ensuring the LO generator operates at a frequency that is not harmonically related to the PA output frequency. Specifically, the LO frequency is set such that when divided by K, it does not produce frequencies that coincide with PA output harmonics, thereby eliminating the corruption pathway while maintaining frequency separation.
2Adaptability or versatility
If mixers are used to generate in-phase and quadrature signals, then signal generation capability is improved, but power consumption increases and spurious harmonics are generated
Solution Approach 1:
The patent extracts and eliminates the mixer components from the signal generation path. Instead of using mixers to generate in-phase and quadrature signals, the system directly generates these signals through the frequency divider and buffer stages, removing the source of spurious harmonics and reducing power consumption while maintaining the required signal generation capability.
3Stability of the object's composition
If buffers and synthesizer are used to maintain frequency and phase matching, then signal integrity is improved, but device complexity and power overhead increase
Solution Approach 1:
The patent makes the frequency divider circuit perform multiple functions: it not only divides the frequency by factor K to achieve frequency separation, but also inherently provides phase relationship management and signal distribution to multiple outputs. This multi-functionality eliminates the need for separate synthesizer and buffer components, reducing device complexity while maintaining frequency and phase matching.
Data Source
AI summary
A local oscillator (LO) generator architecture using a wide tuning range oscillator is disclosed. In one embodiment, a wide tuning oscillator based LO generator system includes a wide tuning range oscillator for generating a signal with a first initial frequency or a second initial frequency in response to a control voltage, a first frequency controlling circuit for converting the first initial frequency of the signal into a final frequency, and a second frequency controlling circuit for converting the second initial frequency of the signal into the final frequency.