Adaptive Notch Filter Timing for Sweeping Interference Tracking
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Solution Overview
Problem
Existing adaptive notch filters struggle to effectively eliminate sweeping interference with high dynamic frequency changes, particularly when the interference is intermittent or has frequency jumps, leading to incomplete removal due to delayed tracking and reset mechanisms.
Innovation Solution
An adaptive filter device comprising a detector circuit, delay circuit, tracker circuit, and notch filter circuit, where the detector circuit detects sweeping interference and provides a first trigger signal, the delay circuit delays the tracker circuit for a predefined or adjustable time, and the tracker circuit estimates and tracks the interference frequency, enabling the notch filter to substantially eliminate it.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the tracking circuit is reset regularly to detect new interference frequency, then the detection capability is improved, but the tracking continuity deteriorates causing inability to remove interference at beginning and end of periods
Solution Approach 1:
The delay circuit is configured to delay the reset signal to the tracker circuit by a predetermined time period. This preliminary timing adjustment ensures that the tracker circuit continues tracking the interference frequency through the reset period, preventing gaps in tracking coverage at the beginning and end of interference periods while still allowing the detector circuit to detect new frequencies.
2Speed
If the adaptive notch filter tracks sweeping interference with high dynamic frequency, then the tracking speed is improved, but the tracking accuracy deteriorates due to delayed estimation
Solution Approach 1:
The delay circuit acts as an intermediary between the detector circuit and the tracker circuit. By introducing a controlled time delay to the reset signal, it allows the tracker circuit to maintain continuous tracking operation during the frequency sweep detection and reset process, thereby preserving both tracking speed and accuracy that would otherwise be compromised by immediate resetting.
Data Source
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AI summary
In one embodiment an adaptive filter structure comprises a detector circuit (10) configured to receive an input signal (Sin), to detect a presence of a sweeping interference in the input signal, and upon detection of such sweeping interference to provide a first trigger signal (T1) to a delay circuit (20), wherein the first trigger signal (T1) comprises a first frequency indication (f1); the delay circuit (20) is configured, upon receiving the first trigger signal (T1), to provide a second trigger signal (T2) to a tracker circuit (30) after an adjustable amount of time; the tracker circuit (30) is configured, upon receiving the second trigger signal (T2), to estimate a frequency of the sweeping interference using a second frequency indication (f2), to track the estimated frequency and provide the estimated frequency as a third frequency indication (f3) to a notch filter circuit (40); and the notch filter circuit (40) is configured to substantially eliminate the sweeping interference from the input signal (Sin) using the third frequency indication (f3) and therefrom provide an output signal (Sout).