FIR Filter Coefficient Calculation for Multi-Function Signal Generation
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Solution Overview
Problem
Existing FIR filter technologies face challenges in calculating filter coefficients efficiently for high-speed digital signals and in realizing multiple functions with a single FIR filter, especially when dealing with a large number of taps, leading to impractical processing times and complexity.
Innovation Solution
A signal generation device with a filter coefficient calculation device that calculates transfer functions for multiple FIR filter functions, allowing for the selection and inverse Fourier transform of these functions to obtain impulse responses as filter coefficients, enabling high-speed calculation and realization of multiple functions with a single FIR filter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of taps of the FIR filter is increased to process ultra high speed digital signals (e.g., 30 Gbit/sec), then the processing capability and functionality are improved, but the calculation time of the filter coefficient becomes excessively long and impractical
Solution Approach 1:
The patent segments the filter coefficient calculation process into multiple independent steps: obtaining frequency characteristics, performing inverse Fourier transform, and extracting impulse response. This segmentation allows each step to be optimized independently and enables parallel processing, significantly reducing the overall calculation time while maintaining the ability to handle ultra high speed signals with large numbers of taps
Solution Approach 2:
The patent performs preliminary actions by pre-calculating and storing frequency characteristics of the transmission line before filter coefficient calculation. This pre-computed data is then reused in the inverse Fourier transform step, eliminating the need to recalculate transmission line characteristics repeatedly and thereby reducing the total computation time for filters with large numbers of taps
2Reliability
If separate FIR filter devices are used for each function, then the reliability and performance of each function is ensured, but the device complexity and the number of required components increase
Solution Approach 1:
The patent implements a universal FIR filter device that can perform multiple functions by dynamically changing its filter coefficients. The same hardware infrastructure (signal generation means, FIR filter, and coefficient calculation means) supports various functions including emphasis, de-emphasis, and equalization by loading different coefficient sets, thereby eliminating the need for separate dedicated devices for each function while maintaining optimal performance
Solution Approach 2:
The patent introduces dynamic reconfigurability to the FIR filter system, allowing the filter coefficients to be changed in real-time based on the required function. This dynamic adaptation enables a single device to switch between different functions (emphasis, de-emphasis, equalization) by loading appropriate coefficient sets, reducing device complexity while preserving function-specific performance through optimized coefficients for each mode
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for the efficient calculation of filter coefficients for FIR filters with a large number of taps at high speed and enables the realization of multiple functions, simplifying the processing and reducing the complexity of calculating filter coefficients.
Implementation Method 1
filter coefficient calculation means for performing inverse Fourier transform on the transfer function selected by the selection means or a product of the transfer functions selected by the selection means to obtain an impulse response of the finite impulse response filter as the filter coefficient
Data Source
AI summary
A filter coefficient calculation device includes a function unit that has a plurality of functions to be executed by an FIR filter, a function selection unit that selects one or a plurality of functions from among the plurality of functions, and a filter coefficient calculation unit that calculates a filter coefficient in the selected one or plurality of functions, and is configured such that the function unit includes a first transfer function calculation unit, a second transfer function calculation unit, and a third transfer function calculation unit which calculate a transfer function of the FIR filter in the respective functions, and the filter coefficient calculation unit performs inverse Fourier transform on the transfer function in the selected one function or a product of the transfer functions in the plurality of functions to obtain an impulse response of the FIR filter and calculates the impulse response as the filter coefficient.