Multiplexed AC Signal Sampling to Eliminate Time Skew
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Solution Overview
Problem
Existing signal conditioning methods for AC sensors like LVDTs and resolvers are costly, large, and power-intensive due to separate anti-aliasing filters and multiplexing, which introduces time skew errors when sampling multiple signals simultaneously.
Innovation Solution
A signal convertor system with first and second multiplexers, an analog-to-digital converter, and a processor that multiplies samples by sine and cosine vectors to determine signal magnitude and mechanical angle, allowing simultaneous sampling of AC sensor signals to eliminate time skew and position slewing errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate anti-aliasing filters and multiplexers are used for each AC sensor signal, then signal conditioning accuracy is improved, but device complexity, size, and power consumption increase
Solution Approach 1:
The patent combines multiple AC sensor signals (I and Q channels) into a single complex signal path, sharing common anti-aliasing filters and multiplexers between channels. This merging approach maintains signal conditioning accuracy through proper complex signal processing while reducing the number of discrete components required for each channel.
Solution Approach 2:
The patent implements universal anti-aliasing filters and multiplexers that serve multiple functions by processing both I and Q channel signals simultaneously. The same hardware infrastructure handles different signal types through software-configurable processing, eliminating the need for dedicated components for each signal path.
2Device complexity
If multiple signals are fed through a common multiplexer, then device complexity is reduced, but time skew errors are introduced into the signal processing
Solution Approach 1:
The patent performs preliminary buffering and timing compensation for signals passing through the common multiplexer. By pre-sampling signals and implementing timing alignment algorithms, the system compensates for multiplexer-induced time skew before further processing, maintaining synchronization between I and Q channels.
Solution Approach 2:
The patent implements feedback mechanisms that measure and compensate for time skew introduced by the common multiplexer. Timing error detection and correction algorithms adjust signal phases dynamically to maintain precise timing relationships between multiple sensor signals despite shared multiplexing resources.
3Measurement precision
If separate processing paths are used for each AC sensor signal, then signal processing accuracy is improved, but conversion throughput decreases
Solution Approach 1:
The patent merges multiple signal processing paths into a unified complex signal processing architecture. By treating I and Q channels as interconnected components of a single complex signal rather than separate real signals, the system achieves high processing accuracy through coordinated complex arithmetic while increasing throughput by eliminating redundant processing steps.
Data Source
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AI summary
A signal convertor (10) includes a first sensor configured to generate a first signal and a second signal and first and second multiplexers (20a-e) configured receive the first and second signals, respectively, and generate samples. The signal convertor also includes an analog-to-digital (A/D) convertor (30) configured to convert the samples and a processor configured to multiply the samples by a sine vector and by a cosine vector and determine a magnitude of the first and second signals based upon the product of the samples and the sine vector and the product of the samples and the cosine vector. A method for converting a signal is also disclosed.