Demodulator Noise Removal via Signal Integration and Zone Replacement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The arc-tangent wave detection method for demodulating FM signals can result in erroneous demodulation due to normalization of differential values exceeding the range of 2π, leading to misidentification of pulse noise and signal degradation when using low-pass filters to remove noise, which also removes high-frequency signal components.
Innovation Solution
A demodulator design that includes an integration section with a high-pass filter, an absolute value calculation, and a noise removal section with zone detection and replacement capabilities to identify and correct erroneous demodulation by replacing signal zones with a replacement target signal, ensuring differential values fall within a predetermined range and reducing noise while preserving signal integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a low-pass filter is used to remove pulse noise from weak electric field signals, then pulse noise is removed, but high-frequency signal components are also removed resulting in signal degradation
Solution Approach 1:
The noise removal process is segmented into multiple stages: first integrating the signal to accumulate noise effects, then detecting specific zones where noise occurs, and finally replacing only those specific zones. This segmented approach allows selective noise removal without affecting the entire signal spectrum.
Solution Approach 2:
The invention extracts and identifies specific noise-containing zones from the overall signal using integration and threshold comparison, then removes only those extracted zones while preserving the rest of the signal. This selective extraction approach prevents loss of high-frequency signal components.
2Ease of operation
If normalization of differential values is applied to keep them within a predetermined range, then arc-tangent values are standardized, but erroneous demodulation occurs due to misidentification of pulse noise
Solution Approach 1:
The integration operation is performed preliminarily before noise detection and replacement. By integrating the signal first, the system prepares the signal in a form that makes noise zones detectable through subsequent threshold comparison, enabling accurate noise identification before any replacement occurs.
Solution Approach 2:
The system uses feedback through the integration result to dynamically identify noise zones. The integrated signal is compared with a predetermined value to determine where noise occurs, and this feedback mechanism guides the selective replacement process, improving both standardization and detection accuracy.
Data Source
AI summary
A demodulator includes: a demodulation section that outputs a demodulated signal demodulated from a modulated signal; an integration section 60a that integrates the demodulated signal; a zone detection section 60b that detects a replacement target zone in the demodulated signal based on an integrated signal output by the integration section; and a replacement section 60c that replaces a signal of the replacement target zone in the demodulated signal with a replacement target signal. A noise can be removed by integrating the demodulated signal by the integration section, and detecting a replacement target zone in the demodulated signal by the zone detection section based on the integrated signal.