Demultiplexing Device Partial Band Processing Circuit Size Reduction
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Solution Overview
Problem
Existing digital multiplexing and demultiplexing technologies require a full Fourier transform circuit for all system bands, leading to increased circuit size even when only a part of the bands are processed, especially when signals from multiple areas are relayed and switched.
Innovation Solution
A demultiplexing apparatus with a demultiplexed-signal selecting and distributing unit, frequency converting and reception low-pass filter units arranged in a tree shape, and a selector unit to switch signal inputs, allowing for partial operation of the circuit and reducing circuit size by processing only the necessary bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a full Fourier transform circuit is used to process all system bands, then signal processing capability is ensured, but circuit size increases even when only a part of bands are processed
Solution Approach 1:
The frequency spectrum is segmented into multiple bands, and the circuit is divided into multiple parallel FFT processing units, each dedicated to processing a specific band. This allows the system to process only the required bands simultaneously, reducing the total number of processing operations needed compared to a full-spectrum FFT, while maintaining the ability to handle multiple frequency bands independently
Solution Approach 2:
Instead of performing FFT processing across the entire system bandwidth, the invention applies FFT processing only to the specific frequency bands that require demultiplexing or multiplexing. By limiting the processing scope to partial bands rather than the full spectrum, the circuit complexity and size are reduced while still achieving the required signal processing functionality
2Adaptability or versatility
If signals from multiple areas are relayed through demultiplexing, switching, and multiplexing, then signal routing capability is improved, but circuit size increases in proportion to the number of areas
Solution Approach 1:
The FFT processing units are designed to be universal and reusable across multiple areas. The same demultiplexing and multiplexing circuitry can handle signals from different areas by configuring the input/output connections and control logic, rather than requiring dedicated circuits for each area. This multi-functional design allows a single circuit implementation to serve multiple geographic areas
Solution Approach 2:
The invention combines the demultiplexing, switching, and multiplexing functions into an integrated circuit architecture where signals from multiple areas can be processed through shared resources. By merging these functions and allowing them to operate in parallel on different frequency bands, the system achieves multi-area signal routing capability without requiring proportionally increasing circuit size for each additional area
Data Source
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AI summary
It is an object of the present invention to obtain a demultiplexing apparatus in which a circuit size can be reduced. The demultiplexing apparatus includes a demultiplexed-signal selecting and distributing unit 130 configured to apply frequency conversion processing and down-sampling processing to one or more reception signals and output the reception signals to a designated output destination, frequency converting and reception low-pass filter units 101 to 114 configured to apply frequency conversion processing and low-pass filter processing to the reception signals and output the reception signals while down-sampling the reception signals, selector units 131 to 136 configured to switch an input source of a signal output to the frequency converting and reception low-pass filter unit at the next stage, reception-channel filter units 121 to 128 configured to subject the signals from the frequency converting and reception low-pass filter units 107 to 114 to waveform shaping with a desired frequency characteristic and output the signals, and a filter-bank control unit 13 configured to generate, based on channel information estimated from one or more reception signals, a control signal for controlling the demultiplexed-signal selecting and distributing unit 130 and the selector units 131 to 136.