Transceiver Oscillator Self-Calibration for Fast Frequency Offset Correction
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Solution Overview
Problem
Existing transceiver circuits face challenges in quickly and accurately calibrating frequency offsets caused by environmental variations, such as temperature changes, which require time-consuming look-up tables and are not suitable for various transceiver circuits and oscillation crystals.
Innovation Solution
A transceiver circuit and self-calibration method that includes a local oscillator, filter circuit, control circuit, and radio frequency signal generator, utilizing a capacitive element and phase locked loop signal to adjust capacitance values dynamically, allowing for immediate and adaptive frequency calibration without the need for a look-up table, suitable for different transceiver circuits and oscillation crystals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional calibration methods using look-up tables are used, then frequency offset calibration can be performed, but the calibration process is time-consuming and not suitable for real-time adjustments
Solution Approach 1:
The system performs self-calibration by automatically detecting frequency offsets and adjusting the capacitive element without external intervention or pre-stored look-up tables. The transceiver circuit uses its own internal resources (phase locked loop signal, filter circuit, control circuit) to identify and correct frequency deviations in real-time, eliminating the need for time-consuming external calibration procedures.
Solution Approach 2:
The control circuit continuously monitors the phase locked loop signal and filtered signal to detect frequency offsets, then automatically adjusts the capacitance value of the capacitive element to correct the deviation. This closed-loop feedback mechanism enables real-time calibration by constantly comparing the actual frequency against the target frequency and making corrective adjustments.
2Device complexity
If fixed calibration parameters are used, then the system is simpler to design, but it cannot adapt to different transceiver circuits and oscillation crystals
Solution Approach 1:
The calibration system dynamically adjusts the capacitance value of the capacitive element based on real-time frequency offset detection. Instead of using fixed calibration parameters, the control circuit continuously modifies the capacitance to match the specific characteristics of different oscillation crystals and transceiver circuits, enabling the system to adapt to various configurations without requiring redesign.
Solution Approach 2:
The system changes the capacitance parameter of the capacitive element to compensate for frequency offsets. By dynamically adjusting this electrical parameter based on detected frequency deviations, the system adapts to different oscillation crystals and transceiver circuits while maintaining a relatively simple overall structure without complex calibration hardware.
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
Enables fast and immediate calibration of frequency offsets, eliminating the need for temperature sensors and look-up tables, and is adaptable to various transceiver circuits and oscillation crystals, ensuring robust performance across different environmental conditions.
Implementation Method 1
The local oscillator includes a capacitive element. The local oscillator is configured to generate a phase locked loop signal based on an oscillation frequency of the oscillation crystal and a capacitance value of the capacitive element.
Implementation Method 2
The filter circuit is configured to generate a filtered signal according to the phase locked loop signal.
Implementation Method 3
The control circuit is configured to adjust the capacitance value to be an adjusted capacitance value according to the filtered signal and the phase locked loop signal.
Data Source
AI summary
A transceiver circuit is configured to couple an oscillation crystal. The transceiver circuit includes a local oscillator, a filter circuit, a control circuit, and a radio frequency signal generator circuit. The local oscillator includes a capacitive element. The local oscillator generates a phase locked loop signal based on an oscillation frequency of the oscillation crystal and a capacitance value of the capacitive element. The filter circuit generates a filtered signal according to the phase locked loop signal. The control circuit adjusts the capacitance value to be an adjusted capacitance value according to the filtered signal and the phase locked loop signal. The local oscillator further generates a calibrated local oscillation signal according to the oscillation frequency and the adjusted capacitance value. The radio frequency signal generator circuit generates a radio frequency signal according to the calibrated local oscillation signal and a baseband signal.