Analysis Filter Bank Using First-Order IIR for Real-Time Sub-Bands
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Solution Overview
Problem
Existing signal processing systems face challenges in achieving real-time processing with low computation cost and low delay, particularly in systems requiring high design flexibility and low power consumption, as conventional filter banks have high computation costs and complex designs.
Innovation Solution
The implementation of an analysis filter bank using parallel first-order infinite impulse response (IIR) filters combined with sub-band response pre-compensators and binomially-combining and rotating devices, which perform frequency-division filtering to generate sub-band signals with low computation cost and low distortion, suitable for real-time signal processing in low power devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional filter banks are used for frequency-division filtering, then signal processing capability is achieved, but computation cost becomes high
Solution Approach 1:
The patent changes the parameter of filter order from higher-order conventional filters to first-order IIR filters. This parameter change dramatically reduces the computational complexity while maintaining the frequency-division filtering capability. The first-order IIR filters require minimal arithmetic operations compared to higher-order filters, thus reducing computation cost and energy consumption while preserving signal processing functionality.
Solution Approach 2:
The patent segments the frequency spectrum into multiple sub-bands using parallel first-order IIR filters. Each filter handles a specific frequency range, and the segmentation allows independent processing of different frequency components. This segmentation approach enables efficient computation by distributing the processing load across multiple simple filters rather than using a single complex high-order filter.
2Productivity
If conventional filter banks are used for frequency-division filtering, then signal processing capability is achieved, but system complexity increases
Solution Approach 1:
The patent simplifies the system by changing the filter parameter to first-order IIR filters, which have a simple structure with only one pole and one zero. This parameter change reduces the number of coefficients and computational operations required, thereby decreasing system complexity while maintaining the ability to perform frequency-division filtering and generate sub-band signals.
Solution Approach 2:
The patent uses multiple copies of the same first-order IIR filter structure with different parameter settings (different center frequencies and bandwidths) to create the parallel filter bank. Instead of designing complex unique filters for each sub-band, the system copies a simple first-order filter template and adjusts its parameters, which reduces design complexity and implementation difficulty.
3Speed
If real-time signal processing is implemented, then processing speed is improved, but delay increases
Solution Approach 1:
The patent uses first-order IIR filters which have a short impulse response and minimal group delay compared to higher-order filters. The parameter change to first-order filters reduces the inherent delay introduced by filtering operations, enabling real-time signal processing with lower latency. This is critical for applications requiring immediate response to input signals.
Data Source
AI summary
An analysis filter bank corresponding to multiple sub-bands, which performs frequency-division filtering on an input signal to generate multiple sub-band signals, the analysis filter bank comprising: a sub-band response pre-compensator which performs a linear filtering on the input signal to generate a response pre-compensated signal, multiple sub-filters with different central frequencies, which perform complex-type first-order infinite impulse response filtering respectively on the response pre-compensated signal to generate multiple sub-filter signals, and multiple binomially-combining and rotating devices based on a set of binomial weights, each of which performs a weighted summation on at least two of the sub-filter signals with the set of binomial weights, and rotates a weighted-summation result with a rotating phase according to a corresponding sub-band central frequency to generate one of the sub-band signals, wherein the at least two of the sub-filter signals are generated by at least two of the sub-filters adjacent in central frequency.