PLL Wideband Feedback Using LC Time Reference for Low Phase Noise
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Solution Overview
Problem
Existing radio frequency (RF) systems face challenges in generating stable waveforms with low phase noise characteristics, which are essential for accurate frequency references and receiver processing, often requiring costly process options or expensive discrete components.
Innovation Solution
Incorporating a wideband feedback loop with a tunable LC-tank circuit based time reference into the Phase Locked Loop (PLL) oscillator to reduce phase noise by adjusting the resonant frequency based on detected phase or frequency errors, introducing a controlled time delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If costly process options or expensive discrete components are used, then phase noise performance is improved, but device cost increases
Solution Approach 1:
The patent replaces expensive discrete components with an integrated LC-tank circuit implemented using standard semiconductor fabrication processes. The time reference circuit is built using常规 process options rather than costly process options, achieving low phase noise without requiring expensive discrete components or special manufacturing processes.
Solution Approach 2:
The patent substitutes a wideband feedback loop with an integrated LC-tank circuit for traditional phase noise reduction methods that rely on expensive discrete components. The feedback loop architecture replaces the need for costly mechanical or discrete electronic components, using instead an integrated circuit approach with standard fabrication processes.
2Manufacturing precision
If a wideband feedback loop with LC-tank circuit is added, then phase noise is reduced, but device complexity increases
Solution Approach 1:
The patent merges the LC-tank circuit directly into the feedback loop of the PLL, creating an integrated time reference circuit. This integration combines multiple functions (frequency division, phase detection, and time reference generation) into a unified circuit structure, reducing the need for separate discrete components and simplifying the overall device architecture.
Solution Approach 2:
The LC-tank circuit serves multiple functions simultaneously: it acts as a frequency divider, a phase shifter, and a time reference generator. This multi-functionality reduces the need for separate dedicated components for each function, thereby reducing overall device complexity while maintaining low phase noise performance.
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 approach enhances phase noise performance without the need for costly components, achieving improved stability and accuracy in RF signal generation.
Implementation Method 1
The LC-tank circuit based time reference circuit introduces a particular time delay. At its resonant frequency, the output frequency of the phase locked loop is controlled to maintain that particular time delay.
Data Source
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AI summary
An apparatus and method for generating a signal. A controlled oscillator generates an output signal having an output signal frequency based on a control input signal. A frequency divider produces a divided frequency output with a frequency of the output signal frequency divided by a value. A detector and filter produce a filtered phase error signal based on a phase difference between the divided frequency output and a frequency reference signal. A variable LC time reference has a resonant frequency based on the low pass filtered error signal and generates a time reference signal with a determined time delay relative to the output signal when the output signal frequency is at the resonant frequency. A time error detector determines an error signal based on a time difference between the output signal and the time reference signal, wherein the control input signal is based on the filtered time error signal.