Interpolating Cubic Spline Filter With Fewer FIR Components
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Solution Overview
Problem
Conventional finite impulse response (FIR) filters require numerous hardware components, making them costly and less suitable for compact, high-speed digital signal processing applications, particularly in VLSI technology and handheld devices.
Innovation Solution
The interpolating cubic spline finite impulse response (IFIR) filter, comprising a pre-filter section using linear phase-B cubic spline functions and an interpolating post-filter section with running average filters, significantly reduces the number of component parts required for digital waveform processing, enabling more cost-effective and compact implementations using VLSI technology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional FIR filters are used to achieve effective band pass or low pass filtering, then filtering performance is improved, but the number of hardware components (multipliers and adders) increases significantly
Solution Approach 1:
The filter is divided into two distinct sections: a pre-filter section that performs initial filtering at a lower sampling rate, and a post-filter section that performs interpolation and final filtering at the higher sampling rate. This segmentation allows each section to be optimized independently, reducing the overall computational complexity while maintaining filtering performance.
Solution Approach 2:
The pre-filter section performs preliminary filtering operations before interpolation, reducing the complexity of the subsequent post-filter section. By preparing the signal in advance with a simpler filter operating at a lower rate, the overall system requires fewer hardware components while achieving the same filtering效果.
2Reliability
If conventional FIR filters are used to provide effective digital signal filtering, then filtering quality is improved, but the physical size of circuit components increases
Solution Approach 1:
Dividing the filter into pre-filter and post-filter sections enables more efficient use of VLSI circuit area. The pre-filter operates at a lower sampling rate requiring fewer resources, and the post-filter uses interpolation to achieve the final high-rate output with reduced computational burden compared to a full-rate conventional FIR filter.
Solution Approach 2:
The system changes the sampling rate parameter between sections - the pre-filter operates at a lower rate (reducing component count), then interpolation increases the rate to the final output rate. This parameter transformation allows achieving high-quality filtering with fewer physical components.
3Manufacturing precision
If conventional FIR filters are used to achieve optimal pass band and stop band performance, then filtering accuracy is improved, but manufacturing cost increases
Solution Approach 1:
The segmented architecture with pre-filter and post-filter sections reduces the total number of multipliers and adders required, directly lowering manufacturing cost. Each section can be implemented with optimized coefficients and structures, further reducing component count while maintaining optimal pass band and stop band performance specifications.
Data Source
AI summary
A filter for high speed digital signal processing. In one embodiment the filter includes a linear, phase-B, interpolating cubic spline filter having a pre-filter section and an interpolating post-filter section. The pre-filter section may be formed to implement any one of a 1-4-1 cubic spline function, a 2-5-2 cubic spline function or a 1-2-1 cubic spline function. The post-filter may be formed using a plurality of running average filters arranged in a cascade (i.e., serial) fashion. The filter can be constructed using significantly fewer independent component parts for a given level of pass band and stop band performance criteria, as compared with a conventional finite impulse response (FIR) filter. The filter is thus ideally suited for implementation with very large scale integration (VLSI) technology, and in a wide variety of electronic devices where high speed digital filtering is required.