Power Line Communication Phase Encoding Noise Resistance
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Solution Overview
Problem
Power line communication systems face challenges due to electrical noise from devices like fans, which interfere with signal transmission and require costly filtering solutions, and broadband systems suffer from signal degradation and electromagnetic compatibility issues, limiting data rates and compatibility with existing infrastructure.
Innovation Solution
A system using crystal oscillators to generate sinusoidal waves, split and phase-shifted signals are alternated to encode control information on a power line, allowing for ultra-narrow band filtering and robust noise resistance, enabling efficient data transmission over power lines without interfering with existing electrical infrastructure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If pulse-position modulation is used to encode data on the power signal, then data transmission capability is improved, but electrical noise from devices like fans interferes with the modulation and corrupts data
Solution Approach 1:
The patent changes the modulation parameter from pulse-position modulation to phase-shift keying (PSK). This parameter change makes the modulation less susceptible to noise because PSK encodes data in the phase of the signal rather than the position of pulses, allowing the receiver to detect phase changes even in the presence of electrical noise from devices like fans.
Solution Approach 2:
The patent replaces the mechanical switching approach of pulse-position modulation with an electronic phase modulation approach. By using phase-shift keying, the system substitutes the mechanical pulse generation and detection with electronic phase comparison, which is more resilient to the electrical noise environment of power lines.
2Object-affected harmful factors
If filtering circuits are added to reduce noise, then noise interference is reduced, but equipment cost and installation complexity increase
Solution Approach 1:
The patent enables the communication system to handle noise internally through phase-based detection algorithms rather than requiring external filtering hardware. The receiver uses phase comparison techniques that inherently reject noise, allowing the system to serve itself in noise reduction without adding complex filtering circuits to the power distribution infrastructure.
Solution Approach 2:
The patent extracts the noise reduction function from the physical filtering hardware and implements it through signal processing algorithms. By removing the dependency on physical filters and using digital or analog phase detection, the system separates the communication function from the power distribution function, allowing noise handling to be achieved through software or simple circuitry rather than complex hardware filters.
3Productivity
If broadband power line communication is used to increase data rates, then data transmission speed is improved, but signal degradation and electromagnetic compatibility issues increase
Solution Approach 1:
The patent changes the frequency parameter by using phase-shift keying at optimized frequencies that balance data rate and reliability. Rather than using wideband frequency modulation, the system uses narrowband phase modulation at frequencies carefully selected to avoid interference with existing power line equipment, thus achieving adequate data rates while maintaining electromagnetic compatibility and reducing signal degradation.
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
The system effectively transmits control signals and data over power lines with high energy density and specific phase encoding, reducing noise interference and extending transmission distance, while avoiding disruptions to other systems and maintaining compatibility with existing power infrastructure.
Implementation Method 1
a first crystal oscillator powered to transmit a sinusoidal wave at a clock frequency from a first output; a second crystal oscillator, which may be powered to transmit a sinusoidal wave at a transmission frequency and a first phase from a second output
Implementation Method 2
a receiver including an ultra narrow band filter, the receiver being electrically connected to the power line
Data Source
AI summary
Disclosed is a system and method for power line control of devices. The system operates in two modes. In mode one, the system operates on an open loop architecture with a controller generating a sinusoidal wave using a crystal oscillator. Control information is added to the sinusoidal wave by alternating the output of two phase shifted waves which have the same frequency and amplitude to form a control signal. The resulting control signal is sent on a power line. The control signal is received using a crystal filter, decoded and converted to executable instructions for the devices and data parameters for sensors. In mode two, the system operates on a hybrid open loop/closed loop architecture where devices are jointly controlled by the controller and the sensors.