Adaptable Power Line Communication Filter Impedance Control
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Solution Overview
Problem
In half-duplex communication systems, the parallel coupling of transmit and receive filters leads to design trade-offs that increase the physical size and cost of the filtering functions, and the high computational resources required by discrete-time delta-sigma modulators for encoding bandpass signals into two-level signals for switch-mode power amplifiers result in increased design complexity and power consumption.
Innovation Solution
The system employs a switch to alter the impedance of the transmit filter during receive mode operations and uses precomputed data sequences with look-up tables to generate a two-level signal for switch-mode power amplifiers, reducing computational resources and power consumption while maintaining high signal-to-noise ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If transmit and receive filters are coupled in parallel to the communication medium, then both filters can operate simultaneously, but the physical size and cost of the filtering functions increase
Solution Approach 1:
The patent applies dynamics by making the transmit filter impedance adjustable based on operating mode. A switch circuit dynamically changes the impedance of the transmit filter between transmit and receive modes, allowing the same filter structure to serve both functions at different times, thereby reducing the need for separate parallel filter structures and decreasing physical size.
2Measurement precision
If discrete-time delta-sigma modulator executes at high rate to achieve high SNR and wide passband, then signal quality improves, but design complexity and cost increase
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the sampling rate of the discrete-time delta-sigma modulator based on the operating mode. During receive mode, the modulator executes at a lower sampling rate reducing complexity, while during transmit mode it operates at higher rates to achieve the required SNR and passband characteristics, thus optimizing the balance between signal quality and design complexity.
3Ease of operation
If modulator and zero-order hold circuit are active during transmission, then signal encoding is achieved, but computational resources and power consumption increase
Solution Approach 1:
The patent applies periodic action by activating the modulator and zero-order hold circuit only during transmit mode operations. During receive mode, these computational blocks are deactivated, creating a periodic on/off pattern that significantly reduces average power consumption while maintaining the necessary signal encoding capability when transmission is required.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces the complexity and cost of communication systems by minimizing the computational resources needed for signal processing, enhancing reliability and power efficiency, and allowing for higher signal levels at the receiver with reduced noise susceptibility.
Implementation Method 1
a transformer configured to galvanically isolate the power amplifier from the communication medium
Implementation Method 2
The switch is coupled to an auxiliary winding of the transformer and to a transmit filter capacitor... The method alters an impedance of the transmit filter with the switch
Data Source
AI summary
A communication system and method of operating the same that includes, in one embodiment, a transmit filter including a transmit filter capacitor, and a receive filter coupled to the transmit filter. The communication system also includes a switch, coupled to an auxiliary winding of a transformer and to the transmit filter capacitor, configured to alter an impedance of the transmit filter during a receive mode of operation of the communication system. In another embodiment, a transmitter is configured to receive an input data stream, and produce a control signal for a switch-mode power amplifier employing a predetermined data sequence selected by the input data stream thereto.