RF Narrowcast Digitizer Subband Segmentation
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Solution Overview
Problem
The high cost and limited availability of ultra-high speed A/D converters required for digitizing narrowcast RF analog signals with a 480 MHz-wide frequency spectrum, as they need a sampling frequency of at least 2.1 GHz and 12-bit resolution, pose a practical limitation in implementing overlay systems for delivering high-definition digital entertainment and telecommunications.
Innovation Solution
Dividing the analog RF narrowcast signal into subband signals, each with a reduced frequency spectrum, allowing for the use of less demanding A/D converters with lower sampling frequencies, thereby reducing costs and improving availability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ultra-high speed A/D converters with sampling frequency of at least 2.1 GHz and 12-bit resolution are used to digitize narrowcast RF analog signals with a 480 MHz-wide frequency spectrum, then the digitization quality and signal fidelity are improved, but the cost and availability become significantly limited
Solution Approach 1:
The patent divides the 480 MHz-wide frequency spectrum into multiple narrower subbands using bandpass filters. Each subband signal is then processed by a separate A/D converter with lower sampling frequency requirements. This segmentation allows the use of more affordable, readily available A/D converters while maintaining overall digitization quality through the combined output of multiple converters.
2Productivity
If a single high-speed A/D converter is used to process the entire 480 MHz frequency spectrum, then the digitization capability is sufficient, but the device complexity and cost increase significantly
Solution Approach 1:
The frequency spectrum is segmented into multiple subbands, each handled by a separate A/D converter with relaxed speed requirements. This approach reduces the complexity specification of individual converters while maintaining the overall digitization capability through parallel processing of multiple subbands.
Solution Approach 2:
The patent transitions from a single high-speed conversion dimension to a multi-dimensional approach where multiple lower-speed converters process different frequency portions simultaneously. This dimensional shift in the frequency domain allows achieving the same overall digitization capability with less demanding individual components.
Data Source
AI summary
Methods and apparatuses are provided to digitize an analog multi-channel RF narrowcast signal in an overlay system by dividing the signal into a plurality of subband signals and digitizing each subband signal using practical A/D converters.