Quarter-Cycle Transpositional Modulation for Bandwidth and Signal Detection
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Solution Overview
Problem
Existing transmission systems face bandwidth limitations and amplitude variation errors in generating and demodulating transpositional modulation signals, which are not effectively addressed by existing carrier modulation methods.
Innovation Solution
The method involves generating quarter-cycle waveforms based on input signals, assembling them into continuous output signals with specific inflections to represent input levels, and demodulating using third harmonic sidebands, phase detection, and fast Fourier transform analysis to overcome amplitude variation and bandwidth limitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If existing carrier modulation methods are used to maximize energy throughout the assigned channel bandwidth, then information bandwidth is maximized, but amplitude variation errors occur in transpositional modulation signals
Solution Approach 1:
The patent segments the carrier cycle into four quarter-cycles, each with distinct amplitude characteristics. By controlling the amplitude in each quarter-cycle independently, the system achieves transpositional modulation without amplitude variation errors, while maintaining maximum information bandwidth through efficient use of the assigned channel bandwidth.
Solution Approach 2:
The patent applies different amplitude characteristics to different portions (quarter-cycles) of the carrier signal. Each quarter-cycle has specific amplitude properties that enable transpositional modulation, allowing the system to achieve both high information bandwidth and zero amplitude variation error by optimizing local signal quality.
2Adaptability or versatility
If transpositional modulation is implemented to convey information without affecting amplitude, frequency or phase, then existing de-modulators cannot detect the signal, but the signal remains undetected by conventional methods
Solution Approach 1:
The patent introduces an intermediary demodulation process that converts the transpositional modulation signal into a form detectable by conventional de-modulators. By transforming the signal through specific processing steps, the system enables detection while maintaining the unique properties of transpositional modulation that conventional methods cannot directly detect.
3Productivity
If quarter-cycle waveforms are assembled into continuous output signals with inflections, then transpositional modulation is achieved, but the signal requires complex demodulation processing
Solution Approach 1:
The patent segments the demodulation process into distinct steps: detecting inflections in quarter-cycle waveforms, measuring amplitude differences, and converting to digital values. This segmentation simplifies the overall demodulation complexity while maintaining high modulation efficiency through the use of quarter-cycle waveform assembly with characteristic inflections.
Data Source
AI summary
Systems and methods for transpositional modulation and demodulation are provided. One such method for generating a signal includes the steps of providing a look-up table having a plurality of quarter-cycle waveforms, each of said quarter-cycle waveforms associated with a respective input level; receiving an input signal; and outputting quarter-cycle waveforms associated with levels of the received input signal. Systems for transpositional modulation are also provided. One such system for generating a signal includes a look-up table having a plurality of quarter-cycle waveforms. Each of the quarter-cycle waveforms are associated with a respective input level, and the look-up table is configured to receive an input signal, and output quarter-cycle waveforms associated with levels of the received input signal.