Mixer-Based Phase-Locked Oscillator for Resonance Drift Control
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Solution Overview
Problem
Conventional dielectric resonator oscillators (DRO) struggle to maintain optimal phase noise under phase lock, especially in extreme environments with temperature changes and mechanical vibrations, leading to increased insertion loss and phase noise.
Innovation Solution
The implementation of an unlocked oscillator configured to operate in an unlocked state and drift in response to environmental changes, coupled with a phase locked loop (PLL) that includes a mixer, phase frequency detector, and a feedback divider, allows for compensation of resonance frequency drift and maintenance of phase lock.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hermetic seal is applied to the DRO to achieve optimum reliability in extreme environments, then reliability is improved, but the mechanical screw becomes inaccessible and device complexity increases
Solution Approach 1:
The patent replaces the mechanical screw tuning mechanism with an electronic phase shift element that can be adjusted remotely via control voltage. This substitution eliminates the need for physical access to the resonator cavity, allowing the hermetic seal to remain intact while enabling frequency tuning and phase adjustment for maintaining phase lock.
2Stability of the object's composition
If the phase shift element adjusts for phase change caused by environmental changes, then phase lock is maintained, but oscillation frequency shifts away from resonator center frequency leading to increased insertion loss and phase noise
Solution Approach 1:
The patent employs a phase-locked loop (PLL) feedback mechanism that continuously monitors the phase difference between the oscillator output and a reference signal. The PLL dynamically adjusts the phase shift element to maintain phase lock while compensating for environmental drift, thereby keeping the oscillation frequency aligned with the resonator center frequency and minimizing phase noise.
3Stability of the object's composition
If the DRO operates at frequency offset from resonance frequency to maintain phase lock, then phase lock is maintained, but phase noise increases due to decreased phase gradient with frequency
Solution Approach 1:
The patent dynamically changes the operating parameters of the DRO by adjusting the phase shift element through the PLL control mechanism. This allows the oscillator to maintain operation at or near the resonator center frequency across varying environmental conditions, optimizing the phase gradient and minimizing phase noise while preserving phase lock stability.
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 effectively maintains phase lock and minimizes phase noise over a wide temperature range and mechanical vibration, simplifying design and reducing the need for mechanical tuning screws or phase shift elements.
Implementation Method 1
a phase frequency detector and the oscillator input port, wherein the phase frequency detector generates a control signal based on a detected phase difference between the reference signal and the mixer output
Implementation Method 2
a mixer having an output port configured to output the unlocked oscillator output mixed with a local oscillator output
Implementation Method 3
an unlocked oscillator configured to oscillate in an unlocked state and output at a resonance frequency configured to drift in response to changes in an operating environment
Implementation Method 4
the control signal adjusts the local oscillator output to compensate for the resonance frequency drift of the unlocked oscillator when mixed with the unlocked oscillator output
Data Source
AI summary
An oscillator and method for maintaining a phase lock is provided. The oscillator may include an oscillator input port for receiving a reference signal, an oscillator output port for outputting an oscillator output, an unlocked oscillator oscillating in an unlocked state and outputting at a resonance frequency configured to drift in response to changes in an operating environment, and a phase locked loop (PLL) including a mixer having an output port configured to output the unlocked oscillator output mixed with a local oscillator output, the mixer output port in communication with a phase frequency detector and the oscillator output port, and the phase frequency detector generating a control signal based on a detected phase difference between the reference signal and the mixer output wherein the control signal adjusts the local oscillator output to compensate for the resonance frequency drift of the unlocked oscillator when mixed with the unlocked oscillator output.