PCIe Signal Bandwidth Determination via Energy Spectrum Analysis
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Solution Overview
Problem
The increasing speed and frequency of PCIe signals in high-speed electronic systems lead to signal integrity issues due to reduced rise time and increased channel loss, necessitating more accurate bandwidth determination to avoid excessive oscilloscope costs and signal-to-noise ratio reduction.
Innovation Solution
A method to determine PCIe signal bandwidth by obtaining the insertion loss of a standard signal, simulating a target analog transmission link, and identifying a target frequency point where the energy spectrum density reaches a preset proportion, allowing for accurate bandwidth selection without requiring high-cost oscilloscopes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the traditional triple sine wave frequency rule (3.5/Tr) is used to determine bandwidth, then the signal integrity can be verified, but the oscilloscope cost increases significantly and signal-to-noise ratio deteriorates
Solution Approach 1:
The patent changes the parameter used for bandwidth determination from the traditional empirical formula (3.5/Tr) to a data-driven approach using actual insertion loss measurements and energy spectrum density analysis. This allows determining the minimum sufficient bandwidth based on real transmission link characteristics rather than relying on conservative empirical rules, thereby reducing oscilloscope cost requirements while maintaining signal integrity verification capability
Solution Approach 2:
The patent replaces the mechanical/electrical measurement approach (direct oscilloscope measurement at high bandwidth) with a computational approach using insertion loss data and energy spectrum density calculations. By substituting physical measurement requirements with data processing, the system can determine bandwidth requirements without needing excessively expensive oscilloscopes
2Measurement precision
If the oscilloscope bandwidth is increased to verify high-speed signals, then signal integrity can be accurately measured, but the signal-to-noise ratio is reduced
Solution Approach 1:
The patent changes the approach from direct high-bandwidth measurement to a two-stage process: first measuring insertion loss at relevant frequencies, then using energy spectrum density analysis to determine the minimum sufficient bandwidth. This parameter transformation allows achieving measurement precision without requiring excessive oscilloscope bandwidth that would introduce noise
3Speed
If the rise time of signals is decreased to increase transmission speed, then data transmission rate improves, but channel loss and signal distortion increase
Solution Approach 1:
The patent implements a feedback mechanism by measuring the actual insertion loss of the transmission link and using this information to determine the appropriate bandwidth. The energy spectrum density is calculated and compared against the insertion loss characteristics, allowing the system to adaptively determine the minimum sufficient bandwidth that accounts for actual channel conditions, thereby optimizing the trade-off between transmission speed and signal integrity
Data Source
AI summary
The present disclosure discloses a method for determining a PCIe signal bandwidth, apparatus and device, and a computer readable storage medium. A target frequency point at which the energy spectrum density of a PCIe signal of a transmission link to be measured, after an output signal of said transmission link is subjected to inverse Fourier transform, reaches a preset proportion (determined according to a measurement error requirement of said transmission link) of that of an original signal is obtained by testing, and the target frequency point is taken as a bandwidth of the PCIe signal of said transmission link. Therefore, accurate high-speed signal bandwidth selection is realized.