Digital Waveform Averaging with Sub-Sample Trigger Alignment
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Solution Overview
Problem
Conventional digital waveform averaging techniques suffer from frequency distortions due to asynchronous sampling and trigger pulses, leading to attenuation of high-frequency components and inefficiencies in noise suppression, especially in low signal-to-noise ratio environments.
Innovation Solution
The method involves dividing the sampling period into uniform sections to detect time displacements of trigger pulses, storing samples in memory bins, and using a low-pass filter and decimator to produce an averaged signal, while an equalizer corrects frequency response distortions, enabling real-time processing of repetitive waveforms without requiring extensive computational resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional digital waveform averaging is performed with asynchronous sampling, then the method is simple to implement, but frequency distortions occur and high-frequency components are attenuated
Solution Approach 1:
The sampling period is divided into multiple sections, with each section assigned to a different memory bin. This segmentation allows samples to be sorted by their temporal position relative to the trigger, enabling accurate reconstruction of waveform timing relationships and elimination of frequency distortions caused by asynchronous sampling.
Solution Approach 2:
The patent introduces a temporal dimension by organizing samples into multiple time-based sections or bins within the sampling period. This dimensional organization preserves the timing information of each sample relative to the trigger, allowing for accurate frequency representation while maintaining the simplicity of the averaging process.
2Measurement precision
If a large number of averaging cycles are performed to improve SNR, then signal-to-noise ratio improves proportionally to square root of averages, but processing time increases significantly
Solution Approach 1:
The patent performs preliminary organization of samples into time-sectioned memory bins during the acquisition phase. This pre-organization allows for efficient averaging computation in the subsequent phase, reducing the computational burden and processing time required to achieve the same SNR improvement that would otherwise require many more averaging cycles.
Solution Approach 2:
The patent creates multiple copies of the waveform data organized in different time sections across multiple averaging cycles. By accumulating these organized copies in memory bins, the system achieves rapid SNR improvement through efficient parallel processing of pre-organized data structures, rather than sequential processing of raw samples.
3Adaptability or versatility
If trigger pulse position varies within sampling interval, then the method accommodates asynchronous operation, but time displacement causes frequency response distortion
Solution Approach 1:
The sampling period is segmented into multiple time sections or bins. Each bin captures samples that occur within a specific temporal window relative to the trigger pulse. This segmentation preserves the temporal relationship between triggers and samples, allowing the system to accommodate variable trigger positions while maintaining accurate frequency response through proper temporal sorting and averaging.
Data Source
AI summary
Noise suppression is achieved by averaging a sequence of repetitive waveforms with correction of frequency distortions, establishing a real time processing of signals. First, the waveforms are processed seriatim, and saved in partitioned memory. Then, the memory contents are merged to form an output digital signal. Initially, an input repetitive signal is sampled with a sampling period T, and divided into K sections along the sampling period so that a kth section, where 0≤k<K, coincides with segment [k·T/K, (k−1)·T/K]. Time displacement detection determines relative positions of trigger pulses and edges of the sampling clock, and the number k of a sampling period section where the trigger pulse appears, keeping k unchanged thereafter. A resultant stream of N·K samples is transmitted through a lowpass filter, followed by decimation by K, to complete the averaging.