Real-Time Oscilloscope Jitter and Noise Analysis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for analyzing joint jitter and amplitude noise in high-speed serial data communication, such as those described in U.S. Patent No. 7,522,661, are inefficient for real-time oscilloscopes as they rely on limited sampling locations and fail to utilize dynamic waveform characteristics, leading to low processing efficiency and incomplete noise analysis.
Innovation Solution
A method and instrument for performing joint jitter and noise analysis that acquires and processes uncorrelated waveforms to calculate timing and voltage displacements across all unit intervals, forming apparent-jitter and apparent-noise arrays, and compensates for these to create arrays representing true jitter and noise, thereby enhancing processing efficiency and utilizing dynamic characteristics of waveforms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the method of U.S. Patent No. 7,522,661 is used to separate jitter from noise using two sampling locations, then measurement precision is improved, but productivity deteriorates on real-time oscilloscopes because most acquired samples are discarded
Solution Approach 1:
The patent segments the waveform analysis into distinct phases: identifying flat-topped regions (low slew rate) for noise measurement and sloped regions (high slew rate) for jitter measurement. This segmentation allows the system to process all acquired samples by routing them to appropriate analysis paths, eliminating the waste of discarding samples while maintaining the precision of selective measurement locations
Solution Approach 2:
The patent applies partial action by performing complete noise analysis only on flat-topped regions where jitter effects are minimal, rather than attempting full joint analysis on all samples. This partial focus on specific waveform regions maintains measurement precision while enabling efficient processing of the entire waveform dataset
2Device complexity
If only two sampling locations per pattern repetition are used, then measurement complexity is reduced, but loss of information increases because dynamic waveform characteristics are not utilized
Solution Approach 1:
The patent applies local quality by assigning different analysis treatments to different regions of the waveform: flat-topped regions receive complete noise analysis while sloped regions receive jitter-focused analysis. This regional differentiation preserves local waveform characteristics and dynamic information without requiring complex unified processing across the entire waveform
Solution Approach 2:
The patent creates a universal analysis framework that processes all waveform samples through a unified workflow that adapts to local waveform characteristics. The system universally applies slew rate calculation, region classification, and conditional analysis routing to every sample, enabling full utilization of waveform data while maintaining analytical simplicity through standardized processing steps
Data Source
Figure 1
Figure 2~4
Figure 5~6
AI summary
A method for determining jitter and noise of an input signal. The method includes acquiring one or more uncorrelated waveform records by an acquisition unit of a test and measurement instrument, determining a correlated waveform from the acquired waveform(s), dividing the correlated waveform into unit intervals, dividing an uncorrelated waveform into unit intervals, measuring a timing displacement (t1) between the correlated waveform and the uncorrelated waveform for each unit interval to form an apparent-jitter array ([t1]), measuring a voltage displacement (V1) between the correlated waveform and the uncorrelated waveform for reach unit interval to form an apparent-noise array ([V1]), calculating a horizontal shift (ts) between the correlated waveform and the uncorrelated waveform for each unit interval to form a compensated edge time array ([ts]), and calculating a vertical shift (Vs) between the correlated waveform and the uncorrelated waveform for each unit interval to form a compensated amplitude voltage array ([Vs]).