Selective Down Conversion for Image Rejection
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Solution Overview
Problem
Current communication systems face challenges in integrating baseband and RF functions on a single chip for multiple wireless communication standards, and existing down conversion methods do not effectively address issues like image rejection and signal quality, particularly when dealing with varying signal strengths.
Innovation Solution
The implementation of selective down conversion processing, where a received signal can be down converted to one of multiple possible intermediate frequencies based on its strength, using either low side or high side injection methods, to optimize signal quality and reduce issues like flicker and DC offset.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed down conversion frequency is used, then the device complexity is reduced, but the image rejection and signal quality deteriorate when dealing with varying signal strengths
Solution Approach 1:
The patent implements dynamic down conversion frequency selection based on received signal strength. The system switches between first and second down conversion frequencies depending on whether the signal strength exceeds a threshold, allowing the receiver to adapt to varying signal conditions and optimize image rejection performance without requiring complex fixed-frequency architectures for multiple standards
Solution Approach 2:
The patent changes the down conversion frequency parameter based on signal strength conditions. By selecting between different intermediate frequencies (first and second down conversion frequencies) according to the received signal strength threshold, the system optimizes signal processing performance while maintaining a relatively simple device architecture
2Reliability
If selective down conversion processing is implemented to improve signal quality, then the image rejection is enhanced, but the device complexity increases
Solution Approach 1:
The patent segments the signal processing path into distinct branches for different signal strength conditions. The receiver is divided into first and second down conversion paths that are selectively activated based on signal strength, allowing optimized signal quality processing without requiring the entire complex system to be always active
Solution Approach 2:
The patent introduces dynamic selection logic that switches between different down conversion processing paths based on real-time signal strength measurement. This dynamic approach enables the system to provide high-quality signal processing only when needed, reducing the effective complexity while maintaining excellent signal quality performance
3Adaptability or versatility
If multiple down conversion frequencies are used to support multiple communication standards, then the adaptability is improved, but the device complexity increases
Solution Approach 1:
The patent implements a universal receiver architecture that can handle multiple wireless communication standards (IEEE 802.11a, g, n, Bluetooth, etc.) by selectively using different down conversion frequencies. The same physical hardware performs multiple functions by switching between first and second down conversion frequencies based on signal strength, eliminating the need for separate dedicated receivers for each standard
Solution Approach 2:
The patent uses parameter changes in the down conversion frequency to achieve multi-standard support. By varying the intermediate frequency parameter (first or second down conversion frequency) based on signal strength and standard requirements, a single receiver can adaptively support multiple communication standards without requiring complex multi-standard hardware architectures
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
This approach allows for improved signal processing by selecting the appropriate down conversion frequency based on signal strength, enhancing image rejection and overall signal quality, thereby supporting multiple communication standards on a single chip.
Implementation Method 1
a received signal is down converted to one of a selected down converted signal having a first intermediate frequency or to a second down converted signal having a second intermediate frequency
Data Source
AI summary
Selective fast image rejection. Selective down conversion processing is performed on a received signal based on the signal strength of that received signal. As few as two possible down conversion frequencies can be employed so that the received signal is down converted either to a first down converted signal having a first intermediate frequency or to a second down converted signal having a second intermediate frequency. If desired, the received signal can either be down converted using low side injection or high side injection down conversion processing. Alternatively, a larger number of possible down conversion frequencies so that the received signal is down converted to one of the possible down conversion frequencies based on the signal strength of the received signal.