Digital Edge Averaged Waveform for Oscilloscope Jitter Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Digital acquisition devices often display signals with 'chatter' due to edges falling within sampling bins rather than directly on the bin boundaries, leading to confusing and less useful representations of digital signals, especially in metastable conditions and with noise.
Innovation Solution
Averaging multiple edge transitions over multiple acquisitions to calculate a weighted average waveform, which is then displayed, effectively eliminating chatter and improving timing accuracy by placing edges between sampling bin boundaries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple edges are displayed to represent a single edge appearing in multiple acquisitions, then the signal representation becomes more complete, but the display becomes confusing with chatter on the X-axis
Solution Approach 1:
The patent merges multiple edge representations by calculating their average position across multiple acquisitions. Instead of displaying separate edges at different X-axis positions, the system combines them into a single averaged edge position, eliminating chatter while preserving the signal representation.
Solution Approach 2:
The patent introduces an intermediary processing step that calculates the average X-axis position of edges across multiple acquisitions. This intermediary computation resolves the conflict between showing complete signal behavior and maintaining display clarity by providing a synthesized representation.
2Measurement precision
If edges are displayed at their actual sampled positions within sampling bins, then timing information is captured accurately, but edges appear to chatter across sampling bin boundaries
Solution Approach 1:
The patent applies periodic averaging across multiple acquisitions, where edge positions are systematically measured in each acquisition and then averaged periodically. This periodic action transforms the unstable, chatter-prone individual measurements into a stable averaged position while maintaining timing accuracy.
Solution Approach 2:
The patent changes the parameter representation from individual edge positions to averaged edge positions. By transforming the data from discrete, variable positions to a computed average position, the system maintains measurement precision while achieving position stability.
3Measurement precision
If the sample clock frequency is increased to provide high resolution on the signal under test, then timing measurement capability is improved, but the complexity of the acquisition device increases
Solution Approach 1:
The patent uses multiple copies of the same sampling process across different acquisitions rather than requiring a single high-frequency sampling system. By repeating the sampling at a lower frequency multiple times and averaging the results, the system achieves high timing resolution without the complexity of a high-frequency sample clock.
Data Source
AI summary
Rising and falling edges captured by a digital acquisition device appear to chatter on the X-axis by two or more sampling bin boundaries as live acquisition continually updates. This leads to a confusing display of limited usefulness. Averaging of multiple edges eliminates chatter while at the same time increases timing accuracy of the edges beyond the abilities of the base acquisition system. An object of the invention is to display a waveform for an averaged digital signal converted from an analog signal received by a signal processing instrument. A plurality of data acquisitions is stored in memory, and for each data acquisition, a number of rising and falling edges are identified. Each rising and falling edge is counted in each data acquisition. From these counted edges, an average waveform is calculated from the plurality of data acquisitions. The average waveform is displayed as an improved representation of the digital signal.