Digital-Tuned Oscillator Frequency Locking Without Clock Glitches
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Solution Overview
Problem
Conventional wireless communication devices face challenges in precisely controlling the frequency of oscillators to synchronize with incoming wireless signals, leading to potential clock glitches and inefficiencies in frequency adjustment.
Innovation Solution
A digital-tuned oscillator system that selectively couples impedances to its resonant tank, using both digital and analog frequency control interfaces to coarsely and finely tune the oscillation frequency, and generates a clock signal to synchronize with the incoming wireless signal, minimizing clock glitches through synchronization techniques and controlled capacitance changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional analog frequency control is used to continuously adjust oscillator frequency, then frequency synchronization is achieved, but clock glitches occur during frequency transitions
Solution Approach 1:
The frequency control is segmented into discrete steps rather than continuous adjustment. The oscillator frequency is controlled by switching between predetermined frequency values, which eliminates the transitions that cause clock glitches while maintaining sufficient synchronization precision for wireless communication.
Solution Approach 2:
The system dynamically selects from multiple predetermined frequency values based on feedback from the incoming signal frequency. The baseband controller adjusts which predetermined frequency is active, enabling adaptive frequency synchronization without the instability of continuous analog control.
2Adaptability or versatility
If digital-to-analog converter is used to generate AFC signal for frequency control, then frequency adjustment is enabled, but additional circuit complexity and power consumption are introduced
Solution Approach 1:
The patent extracts and removes the digital-to-analog converter and low-pass filter from the frequency control path. By using predetermined frequency values directly controlled by digital switching, the system eliminates these analog conversion stages, reducing circuit complexity and power consumption while maintaining frequency adjustment capability.
3Measurement precision
If varactor capacitance is continuously adjusted for frequency tuning, then frequency precision is improved, but clock glitches are generated during transitions
Solution Approach 1:
The varactor capacitance adjustment is segmented into discrete steps corresponding to predetermined frequency values. Instead of continuous capacitance variation, the system switches between specific capacitance values, achieving sufficient frequency precision without the harmful transitions that generate clock glitches.
Solution Approach 2:
The system prepares by establishing a set of predetermined frequency values in advance. This preliminary action allows the oscillator to jump directly to the target frequency without gradual transitions, eliminating clock glitches while maintaining precision through the pre-calculated frequency steps.
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 system effectively synchronizes the oscillator frequency with the incoming wireless signal, reducing clock glitches and improving frequency adjustment efficiency, ensuring stable operation and power conservation in battery-powered devices.
Implementation Method 1
a resonant tank to provide an oscillating current at a frequency indicative of a frequency of operation of the oscillator
Implementation Method 2
providing a resistor in series with the resonant tank to generate an indication of the current
Data Source
AI summary
A technique includes selectively coupling impedances to an oscillator to establish a first frequency of operation of the oscillator. The technique includes repeating the selective coupling in a feedback loop to cause the first frequency to be near a second frequency.