BiQuad Filter Shift-Add Approximation for Low-Power Multiplication

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Solution Overview

Problem

BiQuad filters require significant hardware resources and power due to floating-point multiplication operations, which are computationally expensive and inefficient in digital systems.

Innovation Solution

Approximating multiplication operations using bit-wise shift operations and additions, replacing floating-point multiplications with no-cost bit-wise rewiring and fixed-point arithmetic, thereby reducing hardware usage and power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If floating-point multiplication operations are used in BiQuad filter, then calculation precision is maintained, but hardware resources and power consumption increase significantly

Engineering Contradiction:
Improvecalculation precisionVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent changes the parameter representation from floating-point to fixed-point arithmetic, and replaces multiplication operations with shift and addition operations. This parameter transformation maintains sufficient calculation precision for filter applications while dramatically reducing power consumption and hardware resource requirements.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces expensive floating-point multiplication units with cheaper fixed-point arithmetic units that use shift and addition operations. These simpler computational units consume less power and occupy fewer hardware resources, achieving a cost-effective solution that sacrifices minimal precision for significant resource savings.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Measurement precision

If floating-point multiplication operations are used in BiQuad filter, then accurate coefficient application is achieved, but hardware complexity and computation cycles increase

Engineering Contradiction:
Improvecoefficient application accuracyVSAvoidhardware complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent transforms the computational parameters from floating-point to fixed-point representation and replaces multiplication with shift-add operations. This parameter change simplifies the hardware architecture by eliminating complex multiplier circuits while maintaining adequate coefficient application accuracy for digital filter operations.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent substitutes complex mechanical-like floating-point multiplication operations with simpler fixed-point shift and addition operations. This substitution replaces hardware multipliers with basic arithmetic logic units, reducing device complexity and computation cycles while preserving essential filter functionality.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If floating-point multiplication operations are used in BiQuad filter, then precise signal processing is achieved, but hardware resources and computation time increase

Engineering Contradiction:
Improvesignal processing accuracyVSAvoidcomputation efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent changes the arithmetic parameters from floating-point to fixed-point and replaces multiplication with shift-add operations. This parameter transformation maintains signal processing accuracy sufficient for most applications while dramatically improving computation efficiency by reducing the number of computational cycles required.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces resource-intensive floating-point multiplication units with simpler fixed-point arithmetic units using shift and addition. This substitution improves productivity by enabling faster computation with fewer hardware resources, achieving a practical balance between signal processing reliability and computational efficiency.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Data Source

PatentUS11387822B2Filter and method with multiplication operation approximation capability
Publication Date: 2022.07.12 XMEMS LABS INC
  • US11387822B2 patent drawing
  • US11387822B2 patent drawing
  • US11387822B2 patent drawing

AI summary

A filter is disclosed. The filter includes at least one first multiplication approximation unit, for approximating at least one first multiplication operation corresponding to at least one first coefficient with at least one first bit-wise shift operation; and at least one second multiplication approximation unit, for approximating at least one second multiplication operation corresponding to at least one second coefficient with a plurality of second bit-wise shift operations and at least one addition operation.