Dual Offset Generator System for Precision Voltage Control
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Solution Overview
Problem
Existing digital electrical measurement systems require costly high-precision digital-to-analog converters to achieve precise control over a broad range of offset values, which is necessary for accurate measurements but is economically unfeasible.
Innovation Solution
The system employs two offset generators with different analog step sizes, one with a broad range and high precision, and another with a small range and high precision, allowing for the generation of a desired total offset without the need for a single high-cost converter, with the first offset generator adjusting based on the deviation from the second offset.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single high-precision D/A converter with broad range is used to generate offset, then measurement precision is improved, but device cost increases significantly
Solution Approach 1:
The offset generation function is segmented into two separate offset generators: a first offset generator with broad range but coarse precision, and a second offset generator with narrow range but fine precision. This segmentation allows each generator to be optimized independently, avoiding the need for a single expensive high-precision converter while achieving the same overall precision goal.
Solution Approach 2:
The solution adds a new dimension to the offset generation by introducing a hierarchical structure with two generators operating at different precision levels. The first generator handles the broad voltage range (0-10V) with coarse steps, while the second generator handles fine adjustments within a limited range (-1V to +1V) with precise steps, effectively creating a multi-dimensional offset control space.
2Adaptability or versatility
If a single D/A converter with broad voltage range is used, then offset range is improved, but measurement precision deteriorates due to larger analog step size
Solution Approach 1:
The offset generation is divided into two segments: the first offset generator provides broad voltage range coverage with larger step sizes, while the second offset generator provides fine-grained control with smaller step sizes. This segmentation resolves the contradiction by assigning different precision requirements to different segments of the voltage range.
Solution Approach 2:
Different parts of the offset generation system have different quality characteristics: the first offset generator is optimized for broad range with acceptable precision, while the second offset generator is optimized for high precision within a limited range. This local quality differentiation allows the system to achieve both broad range and high precision where needed.
3Ease of manufacture
If two offset generators with different step sizes are used, then device cost is reduced, but system complexity increases
Solution Approach 1:
The two offset generators are merged into a unified offset control system where their outputs are combined in the measurement line. The control unit coordinates both generators to work together, merging their individual functions into a cohesive system that achieves the desired precision and range while managing complexity through integrated control.
Solution Approach 2:
The control unit implements feedback control by calculating the deviation between the desired offset and the actual offset generated by the second offset generator, then using this deviation to adjust the first offset generator's output. This feedback mechanism automates the coordination between the two generators, reducing the perceived complexity for the user.
Data Source
AI summary
An electrical measurement system for performing a measurement on a device under test has a main unit, a probe unit connected to the main unit, a first offset generator for generating a first offset influencing the measurement, and a second offset generator for generating a second offset influencing the measurement. The first offset generator has a first analog step size and the second offset generator has a second analog step size. The first and second analog step sizes differ from one another.