Dual-Filter A/D Converter for Low-Latency High-Resolution Output
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Solution Overview
Problem
Existing A/D converters with digital filters face challenges in achieving high accuracy while minimizing latency, as the noise-shaping SAR A/D converters require extensive digital conversion processing, leading to increased latency.
Innovation Solution
The implementation of a dual-filter system within the A/D converter, where a second filter with lower resolution outputs data before a first filter with higher resolution, reducing overall latency and increasing accuracy by generating multi-bit digital data through parallel or series connections of filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If digital conversion processing is extended to increase output data accuracy, then measurement precision is improved, but loss of time increases due to increased latency
Solution Approach 1:
The digital filter is divided into a first filter and a second filter that operate in parallel. The second filter processes data with lower resolution requirements and outputs results faster, while the first filter processes data with higher resolution requirements and outputs results with higher accuracy. This segmentation allows the system to provide both low-latency and high-precision output data streams simultaneously.
Solution Approach 2:
The second filter performs partial filtering action with reduced resolution requirements, outputting data that has either lower resolution or smaller effective number of bits. This partial action provides sufficient accuracy for many applications while significantly reducing processing time and latency, whereas the first filter performs complete filtering action for maximum accuracy when needed.
2Measurement precision
If a single high-resolution filter is used to ensure accurate output data, then measurement precision is improved, but productivity decreases due to slower processing speed
Solution Approach 1:
The filtering function is segmented into two parallel filters with different resolution targets. The second filter is optimized for faster processing with lower resolution output, while the first filter is optimized for higher resolution output. This allows the system to maintain high processing speed for basic applications while preserving the capability for high-precision processing when required.
Solution Approach 2:
Different parts of the filtering system are assigned different quality levels. The second filter provides lower resolution output suitable for applications where speed is critical, while the first filter provides higher resolution output for applications where precision is critical. Each filter is locally optimized for its specific quality requirement.
Data Source
AI summary
A digital filter is used in an A/D converter and includes a first filter and second filter. The first filter outputs first digital data by performing filter processing on output of an A/D conversion unit included in the A/D converter. The second filter outputs second digital data by performing filter processing on the output of the A/D conversion unit. The second digital data has either a lower resolution or a smaller effective number of bits than the first digital data does. The second filter outputs the second digital data before the first filter outputs the first digital data.