Multi-Channel Receiver AFC Using Per-Demodulator Frequency Offsets
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional automatic frequency control (AFC) methods for multi-channel receivers fail to accurately correct frequency offsets across different signals, leading to inefficiencies, increased costs, and user experience issues like audio muting due to the need for external tuner adjustments and complex calibration.
Innovation Solution
The implementation of an AFC system that maintains separate frequency offset values for each signal, allowing individual demodulators to correct their respective signals independently, eliminating the need for tuner center frequency adjustments and enabling seamless switching between signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single frequency tuner is used for multiple signals, then receiver cost and footprint are reduced, but frequency offset correction accuracy deteriorates
Solution Approach 1:
The patent divides the frequency correction function into separate segments for each signal source. Each demodulator maintains its own frequency offset value and applies corrections independently, rather than using a single centralized tuner correction. This segmentation allows accurate correction for multiple signals while using a single physical tuner.
Solution Approach 2:
The patent introduces intermediary frequency offset correction values that are applied at the demodulator level rather than at the tuner level. These intermediary corrections act as a bridge between the single tuner output and the multiple signal requirements, enabling precise frequency adjustment for each signal without requiring multiple tuners.
2Reliability
If traditional AFC correction is applied using a reference signal, then frequency offset for that signal is corrected, but other signals with different offsets remain uncorrected
Solution Approach 1:
The patent applies local quality by allowing each demodulator to have its own specific frequency offset correction value tailored to its signal source. Instead of a uniform correction applied to all signals, each signal path receives customized correction parameters, ensuring accurate correction for satellite, terrestrial, and other signals with different frequency characteristics.
Solution Approach 2:
The patent creates a universal frequency correction system that can handle multiple signal types (satellite, terrestrial, etc.) through a single tuner. The system maintains multiple frequency offset values and selects/apples the appropriate correction for each signal, providing multi-functional capability without requiring separate hardware for each signal type.
3Measurement precision
If tuner center frequency is externally controlled for AFC, then frequency offset correction is achieved, but device complexity and calibration requirements increase
Solution Approach 1:
The patent extracts the frequency correction function from the tuner control mechanism and relocates it to the demodulator level. By taking out the correction functionality from the tuner's center frequency control, the system avoids the complexity of externally controlled tuners and switched capacitor networks, while still achieving precise frequency offset correction through software-based adjustments at each demodulator.
Data Source
AI summary
Systems and methods for performing automatic frequency control are provided. Instead of relying on individual frequency tuners for each channel of a multi-channel receiver system, the present subject matter uses a single frequency tuner for receiving each channel of the multi-channel receiver system. A locked demodulator may be designated as a reference demodulator and frequency offset values associated with the reference demodulator may be applied to other demodulators of the multi-channel receiver. These frequency offset values may be used by individual demodulators of each channel for correcting corresponding frequency offsets.