Power Line Communications Apparatus Using Digital Signal Synthesis
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Solution Overview
Problem
Power line communication (PLC) transmitters and receivers face inefficiencies due to high power dissipation and the need for costly components to drive large currents and filter signals, while also requiring spectral purity, which limits their efficiency and increases component costs.
Innovation Solution
The apparatus employs a direct digital synthesizer and delta-sigma modulator to generate digital signals, a CMOS buffer for amplification, and a coupler to efficiently transmit and receive data over power lines, minimizing impedance and using a high-current rated CMOS buffer to drive necessary currents while maintaining spectral purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If linear amplifiers are used for PLC transmission, then signal amplification is achieved, but power dissipation increases significantly
Solution Approach 1:
The patent replaces traditional linear analog amplifiers with a digital signal processing system consisting of a direct digital synthesizer and CMOS buffer. The DDS generates the modulated signal digitally, and the CMOS buffer provides digital-to-analog conversion and buffering, eliminating the need for power-hungry linear amplifiers while maintaining signal integrity and reducing power dissipation.
2Manufacturing precision
If filtering is performed prior to power amplification, then spectral purity requirements are met, but component costs and device complexity increase
Solution Approach 1:
The patent replaces traditional analog filtering circuits with digital signal processing techniques. The direct digital synthesizer inherently generates spectrally pure signals through digital synthesis, and the system uses digital filtering methods instead of multiple analog filters, thereby meeting spectral purity requirements while reducing component count and complexity.
3Power
If PLC transmitters drive large currents on power lines, then voltage requirements are met, but power dissipation and component costs increase
Solution Approach 1:
The patent uses a CMOS buffer instead of traditional high-power analog amplifiers to drive the current on the power line. The CMOS buffer efficiently switches current in a digital manner, reducing continuous power dissipation while still delivering the required voltage and current levels for PLC transmission.
Solution Approach 2:
The direct digital synthesizer generates signals through periodic switching of current at the modulation frequency, allowing the system to deliver average power efficiently through pulsed current delivery rather than continuous high current, thereby reducing overall power dissipation.
Data Source
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AI summary
Apparatus and system for communicating data via a power line. The apparatus comprises a transmitter comprising a modulator for generating a second digital signal based on input data; a digital buffer for amplifying the second digital signal to generate a third digital signal; a filter for filtering the third digital signal to generate an analog output waveform; and a coupler for coupling the analog output waveform to the power line.