PHY Latency Measurement Using Gray Code Counters

The patent introduces a dedicated timing measurement unit as an intermediary component within the PHY interface. This separate unit specifically handles timing measurements using Gray code counters, isolating the complex measurement functions from the main data path. The timing measurement unit acts as a mediator that provides precise latency measurements without complicating the overall interface design, as it operates independently with its own counter resources.

The patent segments the PHY interface into distinct functional components: a data path for normal communication and a separate timing measurement path for latency measurement. By dividing the interface into these independent segments, each with specialized functionality, the system achieves high measurement precision without overwhelming complexity. The timing measurement segment uses dedicated counters that operate independently from the data transmission segment.

The patent implements free-running counters that continuously count clock cycles without interruption or reset. This continuous counting provides an unbroken timing record that accurately captures the transit latency even during high-speed data transmission. The counters operate continuously in the background, ensuring that timing measurement is not disrupted by the high-speed communication activities, thereby maintaining measurement accuracy alongside high transmission speeds.

The patent replaces traditional mechanical or software-based timing measurement mechanisms with a hardware-based Gray code counter system. This hardware substitution provides more reliable and accurate timing measurements at high speeds, as the counters are specifically designed to operate reliably at the high clock frequencies required for modern high-speed interfaces like PCIe and USB 3.0.