Multi-Channel Receiver AFC Using Demodulator-Specific Offset Correction
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Solution Overview
Problem
Traditional AFC methods for multi-channel receivers fail to correct frequency offsets across multiple signals effectively, leading to inefficiencies, increased costs, and a poor user experience due to signal loss and decoding errors, particularly in systems with satellite and terrestrial signals using frequency division multiplexing.
Innovation Solution
Implementing a universal AFC method that maintains separate frequency offset values for each signal, allowing demodulators to correct their respective frequencies independently, eliminating the need for tuner adjustments and reducing hardware complexity.
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 becomes ineffective for signals with different offsets
Solution Approach 1:
The patent divides the frequency offset correction function into separate demodulator-specific corrections. Each demodulator maintains its own frequency offset value and applies independent correction, allowing multiple signals with different frequency offsets to be processed correctly by a single shared tuner.
Solution Approach 2:
The patent applies different frequency offset correction values to different demodulators based on their specific signal characteristics. Each demodulator has its own locally optimized frequency offset correction, enabling effective correction for satellite, terrestrial, and other signals with different offsets.
2Measurement precision
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 segments the frequency offset correction process by maintaining separate frequency offset values for each demodulator and signal type. Instead of a single reference-based correction, each demodulator has its own measured and applied correction value, enabling precise correction for multiple different signals simultaneously.
3Measurement precision
If tuner center frequency is externally controlled to correct frequency offsets, then frequency accuracy improves, but device complexity and calibration requirements increase
Solution Approach 1:
The patent extracts the frequency offset correction function from the tuner and relocates it to the demodulators. Each demodulator independently measures and applies its own frequency offset correction, eliminating the need for external tuner center frequency control and associated calibration complexity.
Solution Approach 2:
Each demodulator performs self-correction by measuring its own frequency offset and applying the appropriate correction independently. This self-service approach eliminates the need for complex external control mechanisms and calibration procedures.
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.