Digital Filter Circuit Using Correction Values for Cutoff Attenuation
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Solution Overview
Problem
Existing digital filters require increased calculation amounts and memory sizes to achieve satisfactory attenuation characteristics at cut-off frequencies, leading to larger memory requirements.
Innovation Solution
A filter circuit with an input terminal, output terminal, memory, and processor that compares input and output values, applies correction values based on the comparison results, and calculates output values using these corrected values to reduce the required calculation amount while maintaining satisfactory attenuation characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple stages of buffers are added to increase calculation amount, then attenuation characteristics at cut-off frequency are improved, but memory size increases
Solution Approach 1:
The patent changes the calculation parameters by introducing a correction value mechanism that adjusts the output value based on comparison results. Instead of increasing buffer stages, the system modifies the calculation process by adding correction values (first correction value or second correction value) to achieve satisfactory attenuation characteristics with reduced memory requirements.
Solution Approach 2:
The patent replaces the mechanical approach of adding more buffer stages with a computational correction mechanism. The processor compares input and output values, determines appropriate correction values based on comparison results, and applies these corrections to achieve the desired attenuation effect without physically increasing the buffer memory structure.
2Manufacturing precision
If multiple stages of buffers are added to increase calculation amount, then attenuation characteristics at cut-off frequency are improved, but device complexity increases
Solution Approach 1:
The patent extracts the essential function needed for attenuation (correction of output values) and implements it through a simplified mechanism. Instead of incorporating multiple buffer stages, the system extracts and applies only the necessary correction values based on comparison results, reducing device complexity while maintaining attenuation performance.
Solution Approach 2:
The patent performs preliminary comparison between input and output values before final output generation. The processor compares values in advance, determines the appropriate correction value to apply, and then applies this correction to achieve the desired attenuation effect, simplifying the overall device structure compared to multiple sequential buffer stages.
Data Source
AI summary
A filter circuit includes a processor configured to compare a current input value with a last-time output value, add a first correction value to the current input value and to the last-time output value if a comparison result between the current input value and the last-time output value is greater than a predetermined value, and add a second correction value smaller than the first correction value to the current input value and to the last-time output value if the comparison result is smaller than or equal to the predetermined value, and calculate a current output value based on the current input value and the last-time output value to each of which the first correction value or the second correction value has been added.