Power Line Carrier Noise Suppression Circuit
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Solution Overview
Problem
The existing technologies face challenges in accurately distinguishing and suppressing strong interference noise from power line carrier channels, where the frequency difference between strong and weak signals can be up to 50 dB, making it difficult to separate and enhance the weak carrier signal effectively.
Innovation Solution
A method and circuit structure that utilize a high-pass filter, amplitude limiting, and time-sharing processing to differentiate between strong and weak signal frequencies, routing them to appropriate suppression circuits for noise reduction, ensuring the weak carrier signal is not compressed and the strong noise is effectively suppressed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a noise suppression circuit is designed to suppress strong sine wave signal with lower frequency, then the weak sine wave signal with higher frequency is improved, but when frequencies are swapped the strong sine wave signal is enhanced and weak sine wave signal is suppressed
Solution Approach 1:
The frequency band is segmented into multiple sub-bands using a cascade of high-pass filters (first high-pass filter for 40-150 kHz, second high-pass filter for 150-500 kHz). This segmentation allows different suppression circuits to handle different frequency ranges independently, resolving the contradiction by making the system adaptable to various frequency configurations while maintaining effective noise suppression.
Solution Approach 2:
The system dynamically adapts to different frequency scenarios through time-sharing processing channels. The first and second time-sharing processing channels are selectively activated based on the actual frequency relationship between strong interference noise and carrier signal, allowing the system to switch between different suppression strategies to maintain optimal performance across varying conditions.
2Measurement precision
If the weak carrier signal is enhanced through superposition, then the amplitude changes slightly, but it is very difficult to directly separate and measure it through dedicated circuits or instruments
Solution Approach 1:
The invention extracts the weak carrier signal from the strongly interfered composite signal by using high-pass filters to remove low-frequency strong interference noise. The time-sharing processing channels then selectively process different frequency components, effectively separating and enhancing the weak carrier signal for accurate detection and measurement.
Solution Approach 2:
The patent introduces intermediary processing stages including high-pass filters and time-sharing processing channels that act as mediators between the raw composite signal and the final detected carrier signal. These intermediaries facilitate the separation and enhancement of the weak carrier signal by progressively filtering and processing different frequency components.
3Measurement precision
If frequency distinction and time-sharing processing are implemented, then strong sine wave signal can be suppressed in the whole channel, but the circuit complexity increases
Solution Approach 1:
The frequency channel is segmented into multiple sub-channels using cascaded high-pass filters, with each segment handled by dedicated time-sharing processing channels. This segmentation enables effective noise suppression across the entire frequency range while organizing the circuit complexity into manageable, modular sections.
Solution Approach 2:
The time-sharing processing channels are designed to handle multiple functions: they can process both strong interference noise suppression and weak carrier signal enhancement depending on the active channel. This multi-functionality reduces overall circuit complexity by using shared components rather than separate dedicated circuits for each function.
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 allows for accurate distinction and suppression of strong interference noise, improving the signal-to-noise ratio by routing the weak carrier signal to appropriate processing channels, ensuring the weak signal is not weakened, and maintaining effective noise suppression across the 40 kHz to 500 kHz frequency band.
Implementation Method 1
The carrier signal extracted from the receiving point is introduced into the high-pass filter, eliminating the interference signal within lower limit of frequency interval mixed in carrier signal
Implementation Method 2
The mixed signal is conducted with amplitude limiting through a nominal level amplitude limiting circuit, so as to obtain the mixed amplitude limiting signal within nominal level range
Data Source
AI summary
A suppression method for strong interference noise of power line carrier channel is based on the processing process to carrier signals transmitted in standardized frequency interval among power line transmission regional area. According to the situation of frequency lead or lagging carrier of strong interference noise, the pending signals are respectively transmitted to a first suppression circuit (3) of which the frequency of strong interference noise signal is lower than the frequency of carrier signal, and a second suppression circuit (5) of which the frequency of strong interference noise signal is higher than the frequency of carrier signal through split-flow processing channel module to process the amplitude limiting signal, and then output signals of the first suppression circuit (3) and second suppression circuit (5) are conducted with differential mixing and output to complete the noise reduction process. Regardless of any position of strong interference noise and carrier in channel, the suppression of strong interference noise of power line can be realized by this method. In the major premise of the weak carrier signal not being suppressed, this method has realized that the strong interference noise is effectively attenuated.