Selectable IF Demodulator Using Dynamic Filter Switching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing demodulators in communications devices face limitations in sensitivity and frequency selectivity due to the use of filters, which restrict the range of input signals that can be demodulated, and often require complex receiver designs for down conversion.
Innovation Solution
A method and apparatus for demodulating input signals in a selectable intermediate frequency system, comprising a front end module, a filter with configurable characteristics, and a phase lock loop (PLL), allowing for high sensitivity demodulation by selecting filter bandwidth, center frequency, and type to match the input signal, and enabling demodulation of various frequency ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a relatively high-bandwidth filter is used, then the demodulator can process input signals over a wide frequency range, but the sensitivity is relatively low
Solution Approach 1:
The patent implements dynamic filter bandwidth adjustment by switching between multiple filter configurations (first filter with higher bandwidth and second filter with lower bandwidth) based on the detected frequency range of the input signal. This dynamic adaptation allows the system to optimize sensitivity for each specific frequency range, resolving the contradiction between wide frequency coverage and high sensitivity.
Solution Approach 2:
The system changes the filter parameters (bandwidth and center frequency) according to the input signal characteristics. By detecting the frequency range and selectively applying different filter configurations, the system maintains optimal sensitivity across various frequency ranges while preserving the ability to handle wide frequency spectra.
2Reliability
If a relatively low-bandwidth filter is used, then the demodulator achieves high sensitivity, but the input signal frequency range is limited
Solution Approach 1:
The system dynamically selects between first and second filter configurations based on the input signal's frequency range. When signals within a first frequency range are detected, the first filter is applied; when signals fall within a second frequency range, the second filter is applied. This dynamic selection enables the system to achieve high sensitivity for specific frequency ranges while maintaining overall adaptability.
Solution Approach 2:
The frequency spectrum is segmented into multiple ranges, each handled by a specialized filter configuration. The first filter handles the first frequency range with optimized sensitivity, while the second filter handles the second frequency range. This segmentation allows each filter to be optimized for its specific range, achieving high sensitivity without limiting overall frequency coverage.
3Device complexity
If down conversion is performed to enable demodulation at various frequencies, then simpler receiver designs and lower speed signal processing are achieved, but the system requires complex filter configurations
Solution Approach 1:
The patent implements a universal filter system that can function across multiple frequency ranges by switching between different filter configurations. The same filter hardware structure is used for both frequency ranges, but its parameters (bandwidth and center frequency) are reconfigured based on the input signal. This multi-functionality reduces overall system complexity compared to having separate dedicated filters for each frequency range.
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 solution enables high sensitivity demodulation of input signals across a wide range of frequencies with simpler receiver designs, improving frequency selectivity and adaptability in communications devices.
Implementation Method 1
The front end module mixes the input signal with an oscillating signal
Implementation Method 2
The PLL demodulates an output frequency based on the output of the filter
Data Source
AI summary
A method and apparatus for demodulating an input signal in a selectable intermediate frequency system is disclosed. The apparatus includes a front end module, a filter, and a phase lock loop (PLL). The front end module mixes the input signal with an oscillating signal. The filter includes at least one characteristic that is selectable to configure an intermediate frequency. The PLL demodulates an output frequency based on the output of the filter.