Adaptive Decimation Filtering for Aliasing Noise and Delay Trade-Off
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Solution Overview
Problem
Existing signal processing systems face challenges in efficiently managing aliasing noise and noise cancellation, particularly in environments with varying noise levels, where existing solutions either compromise on delay time or noise cancellation performance.
Innovation Solution
An adaptive filter apparatus that adjusts the order and attenuation characteristics of a decimation filter based on the noise level of high-frequency components, allowing for optimized noise cancellation and reduced delay time by dynamically changing filter settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a decimation filter is used to reduce aliasing noise, then noise cancellation performance is improved, but delay time increases
Solution Approach 1:
The patent implements dynamic adjustment of the decimation filter order based on the noise level of high-frequency components in the input signal. When noise levels are high, a higher filter order is applied to reduce aliasing noise more effectively. When noise levels are low, the filter order is reduced to minimize delay time. This dynamic adaptation resolves the contradiction by making the filter characteristics variable rather than fixed, allowing optimization of both noise cancellation and delay based on actual signal conditions.
Solution Approach 2:
The patent changes the filter order parameter of the decimation filter based on the detected noise level of high-frequency components. By adjusting this key parameter dynamically, the system can adapt its noise cancellation strength and corresponding delay characteristics to match the actual noise environment, thereby resolving the trade-off between noise reduction effectiveness and processing delay.
2Object-affected harmful factors
If the filter order is increased to reduce aliasing noise, then noise cancellation performance is improved, but processing complexity increases
Solution Approach 1:
The system dynamically adjusts the filter order based on the noise level of high-frequency components, using higher filter orders only when noise levels warrant the additional complexity. This dynamic approach ensures that processing complexity is increased only when necessary for effective noise cancellation, rather than maintaining high complexity unconditionally.
Solution Approach 2:
By changing the filter order parameter adaptively based on noise level detection, the system optimizes the balance between noise cancellation performance and processing complexity. The filter complexity is adjusted to match the actual noise conditions, avoiding unnecessary computational overhead in low-noise environments.
3Loss of time
If the filter order is decreased to reduce delay time, then processing speed is improved, but noise cancellation performance deteriorates
Solution Approach 1:
The patent implements dynamic adjustment of the decimation filter order based on real-time detection of high-frequency noise levels. When noise levels are high, the system increases the filter order to maintain effective noise cancellation. When noise levels are low, the system decreases the filter order to minimize delay time. This dynamic adaptation allows the system to optimize both noise cancellation performance and delay time based on actual signal conditions.
Solution Approach 2:
The system changes the filter order parameter adaptively based on the detected noise level, allowing the delay time and noise cancellation performance to be optimized for the current operating conditions. This parameter adjustment resolves the contradiction by making the filter characteristics variable rather than fixed.
Data Source
AI summary
Provided is a signal processing system including: an adaptive decimation filter apparatus which has a decimation filter which outputs an output signal obtained by down-sampling an input signal, and an aliasing noise detection unit which detects a magnitude of aliasing noise, which is folded back to a frequency lower than a Nyquist frequency in the output signal of the decimation filter by the down-sampling; and a signal processing apparatus which has a filter control unit which adjusts an order of the decimation filter on the basis of the magnitude of the aliasing noise, and an adaptive filter unit which performs filter processing on the output signal of the decimation filter.