Adaptive Reference Frequency Correction for Fast Radio Synchronization
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Solution Overview
Problem
Existing radio communication devices face challenges in generating a stable reference frequency due to variations in crystal oscillators and require additional control circuitry for frequency correction, leading to increased costs and space usage, as well as non-linear control characteristics.
Innovation Solution
A synchronization apparatus that uses a frequency error to convert an uncorrected reference frequency to an exact frequency value through a frequency conversion unit, eliminating the need for external control means and achieving a linear control characteristic, allowing for fast synchronization across channels without altering the reference oscillator frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional control circuitry is used for frequency correction, then frequency synchronization precision is improved, but device complexity and cost increase
Solution Approach 1:
The invention extracts the frequency correction function from the reference oscillator and implements it separately in the signal processing path. The reference oscillator remains simple and uncorrected, while a frequency error calculator and correction mechanism are applied to the signal path, separating the stabilization function from the frequency generation function.
Solution Approach 2:
The invention introduces an intermediary frequency error calculator that measures the frequency deviation and generates correction signals without directly modifying the reference oscillator. This intermediary component enables precise frequency correction through digital signal processing rather than direct analog control.
2Measurement precision
If additional control circuitry is used for frequency correction, then frequency synchronization precision is improved, but device area and cost increase
Solution Approach 1:
The invention replaces analog control circuitry with digital signal processing methods. The frequency error calculator and correction mechanisms are implemented using digital processors rather than analog components, reducing the physical area required while maintaining or improving frequency synchronization precision.
3Ease of operation
If analog control circuitry is used for frequency correction, then frequency adjustment is achieved, but control linearity is poor
Solution Approach 1:
The invention replaces the non-linear analog control circuitry with digital frequency error calculation and correction. The digital processor calculates frequency errors and applies corrections through digital signal processing, providing a linear and predictable control characteristic that is independent of temperature and component variations.
4Measurement precision
If reference oscillator frequency is altered for frequency tracking, then frequency synchronization is improved, but spectral purity and stand-by performance deteriorate
Solution Approach 1:
The invention segments the frequency correction function from the reference oscillator and applies it separately to the signal path. The reference oscillator maintains its stable, uncorrected frequency for spectral purity, while frequency tracking is achieved through separate correction mechanisms applied to the processed signal.
Solution Approach 2:
The invention extracts the frequency correction from the reference oscillator output and applies it independently in the signal processing path. This allows the reference oscillator to remain unchanged and preserve spectral purity, while frequency tracking is achieved through the extracted correction mechanism.
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 solution reduces current consumption, eliminates the need for additional control circuitry, and ensures precise frequency synchronization, enhancing spectral purity and stand-by times by decoupling the frequency adjustment from the phase locked loop arrangement.
Implementation Method 1
This analog control signal is applied to a varactor diode which changes its capacitance in dependence of the applied voltage and therefore the frequency of the crystal oscillator changes, when the capacitance, that builds the resonance circuit varies
Data Source
AI summary
An apparatus and a method provide synchronization of an output signal to a synchronization information. The synchronization is accomplished by providing coupling of a correction control information that controls a signal generator, e.g. a phase locked loop arrangement or a direct digital synthesis arrangement, to its exact frequency to a frequency conversion unit that converts an uncorrected reference frequency to a correct or exact reference frequency. Thereby, the uncorrected reference frequency for the signal generator can be provided by a simple crystal oscillator without any frequency controller. The setting of the signal generator and the frequency conversion unit can be done in a predetermined sequence which enables a user equipment to synchronize its reference frequency to the synchronization information emitted by a communication network.