FIR Filter Coefficient Control for Continuous Slope Adjustment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
IIR filters have limited adjustment capabilities for their amplitude characteristics, particularly in controlling the angle of inclination of the slope portion, which restricts their compatibility with analog filters and requires discrete adjustments, lacking continuity across different filter degrees.
Innovation Solution
A method and device for controlling FIR filters that generate and apply control data to adjust the amplitude characteristics, allowing for non-integer expansions/compressions and shifts in the frequency axis, enabling continuous adjustment of the slope portion's angle of inclination while maintaining compatibility with IIR and analog filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the degree n of the transfer function is adjusted in discrete values to control the angle of inclination of the slope portion of the amplitude characteristic, then the configuration size remains small, but the adjustment precision of the angle of inclination is limited and cannot achieve continuous adjustment
Solution Approach 1:
The patent applies parameter changes by transforming the discrete degree parameter n into a continuous control mechanism. Specifically, it uses expansion/compression ratios (which can be non-integer values) applied to the angular frequency argument of the transfer function to achieve continuous adjustment of the slope angle, while maintaining the original filter structure and avoiding increased configuration complexity.
2Measurement precision
If the sharpness Q and degree n are adjusted to control the angle of inclination, then finer adjustment is possible, but the shape of the amplitude characteristic changes in a different manner and continuity between filters of different degree cannot be maintained
Solution Approach 1:
The patent applies local quality by selectively modifying only the frequency scaling aspect (through expansion/compression ratios) while keeping the fundamental transfer function structure and other parameters unchanged. This localized modification allows continuous adjustment of the slope angle while preserving the overall amplitude characteristic shape and ensuring continuity between different filter configurations.
3Adaptability or versatility
If discrete adjustment of degree n is used to control slope angle, then device complexity remains low, but adjustment flexibility is limited and cannot achieve fine continuous control
Solution Approach 1:
The patent applies universality by designing a control mechanism that handles both integer and non-integer expansion/compression ratios through the same computational framework. The system universally processes different types of input (discrete or continuous) using the same transfer function evaluation method, thereby achieving high adjustment flexibility without increasing device complexity or requiring separate control paths.
Data Source
AI summary
A method for controlling an FIR filter includes generating, based on operation information, a first and second control data, generating a second amplitude characteristic, and setting filter coefficients of the FIR filter based on the second amplitude characteristic. The first control data indicates an amount of expansion/compression in a frequency axis direction of a first amplitude characteristic that corresponds to a predetermined transfer function that is expressed as a function of an angular frequency, and the amount of expansion/compression is an integer value or a non-integer value. The second control data indicates an amount of shift in the frequency axis direction of the first amplitude characteristic. The second amplitude characteristic is generated by expanding/compressing the first amplitude characteristic in the frequency axis direction in accordance with the first control data and shifting the first amplitude characteristic in the frequency axis direction in accordance with the second control data.