PCIe Analyzer Receiver Phase Control for Fast Line Rate Switching
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Solution Overview
Problem
PCIe analyzers face challenges in quickly switching receiver line rates, which can result in missed observations during line rate changes, as existing solutions take up to one millisecond to change line receive rates, hindering debugging and data gathering.
Innovation Solution
The implementation of a circuit and method for multi-rate reception in PCIe analyzers, enabling rapid switching between data rates by using a receiver with a clock input, phase detector, and filter to control the sampling phase, allowing changes in a few nanoseconds without resetting the receiver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If existing receiver line rate switching methods are used, then the receiver can operate at different data rates, but the switching time is too long (up to one millisecond) to observe line rate changes
Solution Approach 1:
The patent implements dynamic line rate switching by enabling the receiver to transition between different data rates (e.g., 2.5 Gbps, 5 Gbps, 10 Gbps) without fixed configuration. The receiver dynamically adjusts its sampling rate and synchronization parameters based on the current line rate, allowing rapid adaptation to changing data rates while maintaining observation capability during transitions.
Solution Approach 2:
The patent changes key operational parameters including sampling rate, clock frequency, and synchronization timing to enable fast line rate switching. By pre-configuring multiple operating modes with optimized parameters for different data rates, the receiver can switch between 2.5/5/10 Gbps modes in a few nanoseconds rather than milliseconds, capturing line rate changes for analysis.
2Measurement precision
If the receiver samples data at a fixed high rate, then sampling precision is maintained, but the receiver cannot quickly adapt to lower data rates without resetting
Solution Approach 1:
The patent designs the receiver to universally handle multiple data rates (2.5 Gbps, 5 Gbps, 10 Gbps) using the same hardware infrastructure. The receiver incorporates a universal sampling mechanism that can operate at different rates by adjusting the sampling clock frequency and phase, eliminating the need for rate-specific hardware configurations while maintaining sampling precision across all modes.
Solution Approach 2:
The receiver employs dynamic parameter adjustment to maintain sampling precision across varying data rates. The sampling clock is dynamically synchronized to match the input data rate, and the phase detector continuously adjusts timing parameters to optimize sampling points. This dynamic adaptation allows the receiver to maintain high measurement precision whether operating at 2.5, 5, or 10 Gbps without resetting the receiver state.
Data Source
AI summary
Methods and apparatus for quickly changing line rates in PCIe analyzers without resetting the receivers. One example circuit for multi-rate reception generally includes: a receiver having a data input, a data output, and a clock input configured to receive a clock signal from a clock generator, the receiver being configured to switch between receiving data at a first data rate and at least one second data rate and to sample data according to the first data rate, wherein the first data rate is higher than the at least one second data rate; a phase detector having an input coupled to the data output of the receiver; and a filter having an input coupled to an output of the phase detector and having an output configured to effectively control a phase of the sampling by the receiver when the data is at the at least one second data rate.