Direct Conversion Receiver with Digital Oversampling Selectivity
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Solution Overview
Problem
Conventional wireless receivers, such as superheterodyne receivers, face limitations in tunability, selectivity, and dynamic range due to reliance on passive filter technology and high-order passive circuitry, leading to increased cost, size, and power consumption, as well as limited frequency agility and signal processing capabilities.
Innovation Solution
A wireless communications device with a multipath architecture that uses programmable digital filters and predictive coders to achieve frequency translation and quantization independently, eliminating the need for high-order passive circuitry and enabling wideband operation without external passive components, thereby enhancing selectivity and dynamic range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional superheterodyne receiver architecture is used, then signal conversion to intermediate frequency is achieved, but the number of circuit components increases leading to increased cost, size and power consumption
Solution Approach 1:
The patent extracts and eliminates the intermediate frequency conversion stage from the conventional superheterodyne architecture. The direct conversion receiver converts the RF signal directly to baseband without requiring an IF stage, thereby removing numerous associated circuit components including IF filters, IF amplifiers, and related passive components, while maintaining signal conversion capability
Solution Approach 2:
The patent merges the frequency conversion and signal processing functions into a single direct conversion stage. The RF signal is converted directly to baseband in one step, combining what were previously separate RF-to-IF and IF-to-baseband conversion stages into a unified architecture, reducing the overall number of components
2Reliability
If high-order passive circuitry is used for filtering, then selectivity is improved, but cost and device complexity increase
Solution Approach 1:
The patent replaces high-order passive analog filters with digital signal processing techniques. Digital filters implemented in the baseband processing stage provide equivalent or superior selectivity without requiring complex passive RLC circuits, high-Q resonators, or multiple cascaded filter stages, thereby reducing component count and complexity
Solution Approach 2:
The patent changes the filtering approach from analog domain with fixed passive components to digital domain with programmable parameters. Digital filters allow dynamic adjustment of filter characteristics through software control, achieving high selectivity without the physical complexity of high-order passive circuits
3Reliability
If conventional analog receivers are used, then frequency translation is achieved, but tunability and dynamic range are limited by front end analog circuits
Solution Approach 1:
The patent replaces analog frequency translation and signal processing with direct digital conversion and digital signal processing. The direct conversion architecture with digital filters and processors in the baseband stage provides superior tunability and dynamic range compared to analog circuits, as digital systems are not subject to analog component tolerances, drift, and non-linearities
Solution Approach 2:
The patent introduces dynamic programmability to the receiver architecture. Digital filters and processing parameters can be dynamically adjusted through software control, allowing the receiver to adapt to different frequency ranges, bandwidths, and signal conditions without physical reconfiguration, thereby enhancing tunability and dynamic range
Data Source
AI summary
The invention described herein is directed to different embodiments of a wireless communications device that can be used in many different applications, such as but not limited to a digital oversampling receiver adapted to select desired signals and to reject undesired signals. In one embodiment, a wireless communications device is disclosed that comprises an architecture for a receiver front end that obviates the need for high order passive circuitry or RC active circuitry to select desired signals and to reject undesired signals.