Multiple Reduced-Bandwidth Processing Paths for CATV Upconversion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional CATV upconversion methods face challenges such as isolation issues, noise, spurious signals, complexity, power consumption, and cost due to single or dual-stage architectures, direct RF approaches introducing distortions, and direct IQ methods being limited by DAC clock rates and noise performance.
Innovation Solution
The use of multiple reduced-bandwidth processing paths with fixed-frequency upconversion, overlapping in frequency to achieve continuous and agile channel placement, allowing for reduced component complexity and noise filtering in inactive regions, thereby simplifying signal processing and reducing power and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single or dual-stage upconversion architecture is used, then full-band CATV coverage is achieved, but isolation issues, noise, spurious signals, and circuit complexity increase
Solution Approach 1:
The patent divides the full-band CATV coverage into multiple reduced-bandwidth processing paths, each handling a specific frequency segment. Multiple processing blocks (202, 204, 206, 208) each handle reduced bandwidth channels and are combined through multiplexers to achieve full-band coverage, thereby reducing the complexity and isolation requirements of individual upconversion stages
Solution Approach 2:
The patent introduces multiplexers (209, 211) as intermediary components that combine the outputs of multiple reduced-bandwidth processing paths. These multiplexers act as mediators to merge the segmented frequency bands into a full-band output, eliminating the need for complex isolation circuits between upconversion stages
2Adaptability or versatility
If direct RF approach is used with high DAC clock rate, then full-band output is achieved, but distortions and noise fold back into the output band
Solution Approach 1:
The patent segments the full-band output into multiple reduced-bandwidth paths, each handled by processing blocks with lower DAC clock rates. This segmentation prevents the need for extremely high DAC clock rates, thereby avoiding the folding of distortions and noise into the output band that occurs in direct RF approaches
Solution Approach 2:
The patent converts the limitation of reduced bandwidth in each processing path into a benefit by allowing the use of lower DAC clock rates. This lower clock rate eliminates the generation of high-frequency distortions and noise that would otherwise fold back into the output band, and the reduced bandwidth paths are then combined to achieve full-band coverage
3Use of energy by moving object
If direct IQ upconversion is used, then power and bandwidth efficiency improve, but DAC clock rate and noise performance become limiting factors
Solution Approach 1:
The patent segments the upconversion process into multiple reduced-bandwidth paths, each with its own processing block. This segmentation allows each block to operate at lower DAC clock rates with better noise performance, while collectively achieving full-band coverage and maintaining power efficiency through the combined output
Data Source
AI summary
A method of channel processing is provided wherein multiple reduced-bandwidth “processing blocks” may be combined at RF to allow for the continuous and flexible placement of multiple-channels across the full or partial CATV output band. Each reduced-bandwidth processing block is associated with a fixed-frequency upconversion. In order to allow for continuous agile channel placement, the processing blocks overlap one another in frequency at RF. In the case where it is not necessary that the full CATV band be available to the combined output, the number of required processing blocks and upconversion paths is reduced and individual processing blocks and upconversion paths may be used to cover multiple non-contiguous frequency bands.