IIR All-Pass Filter Coefficient Layout for Fewer Components
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Solution Overview
Problem
General IIR digital filter design programs do not allow for a reduction in the number of components, limiting the efficiency and complexity of filter designs.
Innovation Solution
A filter design method for IIR-type all-pass filters that includes N signal processors, where the group delay count M is related to the order N as M=N−3, allowing for the calculation and optimization of filter coefficients using the Remez algorithm to reduce the number of components by setting specific filter coefficients to zero or equal values, resulting in a simplified circuit configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If general IIR digital filter design programs are used, then filter design can be performed with standard parameters, but the number of components cannot be reduced
Solution Approach 1:
The patent applies parameter changes by establishing a specific relationship between the group delay count M and filter order N (M=N-3), and by setting specific filter coefficients to zero based on the Remez algorithm optimization. This transforms the standard filter design parameters to achieve component reduction while maintaining design capability
Solution Approach 2:
The patent extracts and eliminates redundant components by setting specific filter coefficients to zero. By identifying which coefficients can be zeroed out based on the optimized design method, unnecessary signal processors and components are removed from the filter structure
2Loss of energy
If the number of components is reduced, then manufacturing cost and power consumption decrease, but filter design flexibility is limited
Solution Approach 1:
The patent changes the design parameters by establishing the M=N-3 relationship and using optimized coefficient selection, which reduces power consumption while maintaining adequate filter design flexibility for practical applications
Solution Approach 2:
The patent applies local quality by selectively zeroing out specific filter coefficients based on their position and importance in the filter structure. This allows certain parts of the filter to be simplified while maintaining the necessary functionality in critical sections
Data Source
AI summary
A filter design method and an IIR-type all-pass filter that enable reduction of the number of components is provided. In the filter design method, a computer designs an IIR-type all-pass filter including N (N is an integer of 4 or more) signal processors connected between an input terminal and an output terminal, a group delay count M of the IIR-type all-pass filter has the relationship “M=N−3” with respect to the order N defined by the number N of signal processors, and the computer executes a process of setting the filter coefficients with even-numbered indices to zero when the order N is an odd number and the index is 1, and setting the filter coefficients with odd-numbered indices to zero when the order N is an even number and the index is 0.