Suggested Review Group: Senior Signal Integrity Engineers and High-Speed Digital Design Architects.
Abstract:
This presentation details significant performance enhancements in the scope client software (post-version 0.11 release), specifically focusing on the GPU acceleration of critical measurement functions: the Clock and Data Recovery Phase Locked Loop (CDRPL) and the Inter-Symbol Interference Pattern (IP pattern, commonly known as the Eye Pattern calculation). While certain edge cases necessitate a fallback to the CPU, the GPU implementation dramatically improves processing speed for the majority of use cases. The demonstration utilizes a Thunderscope connected over 10 Gigabit Ethernet to analyze a 100BASE-T Ethernet differential signal (employing three-level modulation, 125 MHz clock). The system is shown processing high data volumes—acquiring 100 million points per trigger at 8.2 Hz (approximately 800 MS/s data rate)—and integrating over 30 Gigasamples and 7.5 Billion Unit Intervals in near real-time, enabling the visualization and measurement of low-probability jitter events down to the $10^{-7}$ error range.
Performance Enhancements in Scope Client for Signal Integrity Analysis
0:05 Performance Focus: Development efforts post-0.11 are targeting performance improvements for core measurement functions (CDRPL and IP pattern), which were previously recognized as significant processing bottlenecks in complex filter graphs.
0:23 GPU Acceleration Implemented: Both the CDRPL and IP pattern calculations are now GPU accelerated, leading to massive speed increases. A CPU fallback mechanism is retained for cases where the GPU lacks robust 64-bit integer support or for specific input configurations.
0:46 Test Setup: The demonstration uses a Thunderscope acquiring signals from a 100 Megabit Ethernet differential pair. The signals are subtracted to derive the differential waveform, followed by clock recovery at 125 MHz (the 100BASE-T clock rate).
1:02 Measurement Suite: Analysis includes plotting the characteristic three-level eye pattern, measuring the width of the upper and lower eyes, and generating corresponding bathtub curves.
1:13 Initial Acquisition Parameters: A single acquisition captures 100 milliseconds of signal, comprising 50 million points per channel at 500 MS/s. The resulting waveform confirms three-level modulation (PAM-3).
1:56 Single-Shot Measurement Results: A single acquisition measures an approximate 6.3 nanosecond opening on both eyes (horizontal axis) and integrates 12.5 million Unit Intervals (UIs) from 50 million total samples.
2:09 Real-Time Data Streaming: Continuous triggering is initiated, acquiring 100 million points per event at an 8.2 Hz refresh rate. The scope maintains a data throughput exceeding 800 MS/s over a remote 10 Gigabit Ethernet connection.
2:51 High-Volume Integration: In real-time, the system rapidly accumulates data, reaching 15 Gigasamples and 4 billion UIs, and subsequently achieving nearly 30 Gigasamples and 7.5 billion UIs within the demonstration window.
2:57 Jitter Visualization: The rapid integration of high data volumes enables the clear visualization and measurement of low-probability jitter and rare amplitude reductions, specifically identifying events in the $10^{-7}$ (1 in 10 million) Bit Error Rate (BER) range.
3:37 Processing Speed: The entire acquisition, processing, and visualization pipeline is confirmed to operate in real-time, validating the performance impact of the new GPU-accelerated algorithms.