Two-Stage Signal Interpolation With Phase Error Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional signal interpolation techniques require increased memory capacity to achieve an interpolated value close to the true value, as more coefficients need to be stored for phase adjustment.
Innovation Solution
A signal generating device comprising a first digital filter, a second digital filter, a phase calculation unit, a phase-accuracy conversion unit, a memory, a coefficient readout unit, and a gain normalization unit, which calculates and normalizes filter coefficients to generate an interpolated signal without increasing memory capacity by using phase signals to address filter coefficients and correct phase errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If more filter coefficients are stored in memory to achieve higher interpolation accuracy, then the interpolated value approaches the true value more closely, but the memory capacity increases
Solution Approach 1:
The patent divides the interpolation process into two sequential stages: first digital filter and second digital filter. Each filter uses a separate, smaller set of filter coefficients stored in memory. The first filter performs initial interpolation, and the second filter refines the result to correct phase errors. This segmentation allows high interpolation accuracy to be achieved without requiring one large set of coefficients that would consume excessive memory capacity.
2Adaptability or versatility
If a variable digital filter is used to change frequency characteristics, then the filter characteristics can be finely adjusted, but the device complexity increases
Solution Approach 1:
The patent combines two digital filters with fixed filter coefficients into a sequential processing chain. Rather than using one complex variable digital filter that would require dynamic coefficient adjustment mechanisms, the system merges the functionality of two simpler filters. The first filter handles basic interpolation while the second filter corrects phase errors, together achieving fine frequency characteristic adjustment without the complexity of a single variable filter.
Data Source
AI summary
A signal generating device includes a first digital filter unit outputting a first interpolated signal by interpolating an input signal, a second digital filter unit outputting a second interpolated signal by interpolating the first interpolated signal, a phase calculation unit calculating a phase of a digital signal, a phase-accuracy conversion unit calculating first phase signal and second phase signal, a first memory storing filter coefficients, a first coefficient readout unit reading filter coefficients from the first memory and switching filter coefficients of the first digital filter unit, a phase-error calculation unit calculating a phase error signal, a second memory storing filter coefficients, a second coefficient readout unit reading filter coefficients from the second memory, and a gain normalization unit normalizing a gain of the filter coefficients to maintain a constant sum of the filter coefficients and switching filter coefficients of the second digital filter unit.