Finite-State Trigger Matching for Complex Oscilloscope Patterns
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Solution Overview
Problem
Existing digital oscilloscopes face challenges in implementing real-time triggers for complex signal patterns due to the need for significant memory and processing resources, leading to 'blind time' where the instrument is unable to acquire new data while processing stored data for secondary triggers.
Innovation Solution
The use of a finite state machine (FSM) with a symbol generator that converts signal values into symbols, allowing for real-time processing by matching target sequences specified by regular expressions, including counting limitations, to reduce memory requirements and increase processing speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a post acquisition trigger system is used to process complex trigger patterns, then the trigger detection accuracy is improved, but the blind time increases significantly
Solution Approach 1:
The patent applies preliminary action by using a real-time trigger to define a preliminary trigger event and capture data before the complex trigger analysis begins. This preliminary data capture ensures that the data of interest is already in memory when the post-acquisition trigger analysis starts, eliminating the need to stop acquisition for complex pattern matching.
Solution Approach 2:
The patent implements continuity of useful action by allowing the acquisition system to continue operating without interruption. The real-time trigger continuously captures data while the post-acquisition trigger system independently analyzes stored data for complex patterns, ensuring that no data is lost and the system remains continuously productive.
2Adaptability or versatility
If a post acquisition trigger system is used for complex trigger patterns, then the trigger detection capability is improved, but the productivity decreases
Solution Approach 1:
The system performs preliminary data capture using a real-time trigger that continuously acquires data based on simple trigger conditions. This preliminary action ensures that all potentially relevant data is already captured in memory before the complex post-acquisition trigger analysis begins, maintaining high data acquisition rates throughout.
Solution Approach 2:
The patent introduces an intermediary approach where a real-time trigger system handles the high-speed data acquisition while a separate post-acquisition trigger system handles complex pattern analysis. This intermediary architecture allows both simple and complex triggers to operate simultaneously without interfering with each other's performance.
3Adaptability or versatility
If memory banks are used to store data for complex trigger analysis, then the trigger processing capability is improved, but the memory requirements increase
Solution Approach 1:
The patent extracts only the necessary data for complex trigger analysis by using a real-time trigger to define a preliminary trigger event and capture only the relevant portion of the signal. This extraction approach stores only the data that needs to be analyzed for complex patterns, rather than buffering entire periods of acquired data, thereby reducing memory requirements.
Solution Approach 2:
By performing preliminary trigger event definition and data capture before complex analysis, the system prepares only the necessary data subset in memory. This preliminary action ensures that memory is used efficiently to store only the relevant data window needed for complex pattern matching, rather than allocating memory for entire acquisition periods.
Data Source
AI summary
An apparatus that searches for a pattern in a signal is disclosed. The apparatus can be used to implement a real time trigger in an instrument such as a high speed oscilloscope. The apparatus includes a symbol generator and a finite state machine (FSM). The symbol generator receives an ordered sequence of signal values and converts the ordered sequence of signal values into an ordered sequence of symbols, each symbol having a plurality of states. The FSM receives the ordered sequence of symbols and generates a match signal if the ordered sequence of symbols includes a target sequence specified by a regular expression that includes a counting limitation on one of the symbol states. The FSM includes a counting state that includes a counter that counts instances of the one of the symbol states.