Atomic Oscillator Frequency Tuning Without DDS Waveform Loss
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Solution Overview
Problem
Existing atomic oscillators face challenges in maintaining waveform integrity and circuit scale when adjusting resonance frequency variations due to manufacturing variations in buffer gas pressure, particularly in achieving precise frequency outputs without using direct digital synthesizers (DDS), which often deteriorate the waveform.
Innovation Solution
Incorporating a fractional N-PLL with an n-bit decimal setting part to adjust the resonance frequency, allowing the magnetic field generation part to handle boundary digit adjustments while the PLL adjusts higher digits, thereby suppressing circuit scale increase and maintaining waveform quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a direct digital synthesizer (DDS) is used to adjust resonance frequency variations, then frequency adjustment precision is improved, but the waveform of the output signal deteriorates
Solution Approach 1:
The patent segments the frequency adjustment function into two parts: the magnetic field generation part handles adjustments up to the boundary digit (less significant digits), while the fractional N-PLL handles adjustments from the boundary digit upward (more significant digits). This segmentation allows the system to achieve precise frequency adjustment without using DDS, thereby maintaining waveform quality while correcting for manufacturing variations in buffer gas pressure.
2Adaptability or versatility
If additional circuitry is added to adjust all digits of resonance frequency, then frequency adjustment capability is improved, but device complexity increases
Solution Approach 1:
The patent merges the frequency adjustment functions of the magnetic field generation part and the fractional N-PLL into a coordinated system. The magnetic field generation part adjusts less significant digits of the resonance frequency, while the fractional N-PLL adjusts more significant digits. This merging allows comprehensive frequency adjustment capability without requiring additional independent circuits, thus suppressing device complexity while maintaining adaptability.
3Device complexity
If the magnetic field generation part adjusts only up to the boundary digit, then circuit scale is suppressed, but frequency adjustment precision for all digits is reduced
Solution Approach 1:
The fractional N-PLL acts as an intermediary that bridges the limitation of the magnetic field generation part. While the magnetic field generation part is constrained to adjusting only up to the boundary digit, the fractional N-PLL mediates by taking the reference signal and generating a signal including the resonance frequency of the atom with adjusted higher digits. This intermediary function enables precise adjustment of all frequency digits without increasing circuit scale.
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
The solution enables precise adjustment of all resonance frequency digits without deteriorating the output signal waveform, reducing the need for additional circuitry and maintaining frequency accuracy, thus addressing the limitations of existing technologies.
Implementation Method 1
a magnetic field generation part to apply a magnetic field to the atomic cell
Implementation Method 2
an atomic resonance signal outputted from the atomic cell
Data Source
AI summary
An atomic oscillator includes an atomic cell in which an atom is enclosed, a magnetic field generation part to apply a magnetic field to the atomic cell, a reference oscillator which is controlled based on an atomic resonance signal outputted from the atomic cell and generates a reference signal, and a fractional N-PLL which receives the reference signal to generate a signal including a resonance frequency of the atom, in which when a maximum digit of the resonance frequency adjustable by the magnetic field generation part is a boundary digit, the fractional N-PLL can adjust at least a digit one digit higher than the boundary digit.