Feature: Clock and timing electronics


ultimately, limit overall system performance. While phase noise and jitter are


expressed differently, they describe the same underlying timing imperfections. Understanding the relationship between the two is essential for system architects because the dominant timing metric and the performance penalties associated with it vary significantly across applications. Whether optimising wireless network performance or maximising throughput in an AI cluster, timing quality increasingly determines the achievable performance of the entire system.


Figure 1: Maintaining signal integrity at higher data rates requires proportionally lower jitter, making timing performance a critical system design parameter


how timing systems are specified, built and implemented across modern compute infrastructure.


Timing errors scale with system complexity As data rates rise and architectures become more distributed, timing errors that were once isolated to individual components can now propagate across subsystems, reducing performance, limiting scalability and, ultimately, compromising system reliability. Understanding the sources of timing error is therefore fundamental to designing robust timing architectures. At the heart of these challenges is timing


noise, the deviation of a clock signal from its ideal behaviour. Timing noise can be viewed through two complementary perspectives: the frequency domain and the time domain. Both describe the same underlying phenomenon but provide different insights into how timing imperfections affect system performance. Selecting the right timing solution requires understanding which metric is most relevant to the application and over what frequency range or observation interval it must be evaluated. In the frequency domain, timing noise


is characterised as phase noise, a measure of the spectral purity of an oscillator. Phase noise describes how noise energy is distributed around the ideal carrier frequency and is expressed in dBc/Hz at a specified frequency offset. It quantifies short-term frequency instability and is a critical performance parameter in RF and wireless applications, including 5G infrastructure, satellite communications, radar systems and precision instrumentation. Excessive phase noise raises the effective noise floor, reduces receiver sensitivity and limits the ability to detect weak signals in the presence of interference. In the time domain, timing noise is


expressed as jitter, which measures the variation of a clock edge from its ideal timing position. Typically measured in picoseconds or femtoseconds, jitter has become one of the defining constraints in modern high-speed digital systems. Interfaces such as PCI Express, Ethernet, CXL and advanced SerDes links operate with increasingly tight timing margins, where even small amounts of jitter can degrade signal integrity (Figure 1), reduce channel reach, increase bit error rates and,


Synchronising heterogeneous compute architectures As computing platforms continue to increase in performance, scale and architectural complexity, maintaining precise synchronisation has become a critical system-level challenge. Modern AI servers, GPU accelerator cards, SmartNICs, DPUs and networking platforms increasingly integrate multiple heterogeneous processing elements within a single system. CPUs, GPUs, FPGAs, ASICs, memory subsystems and high-speed interconnects each operate with distinct frequency requirements, power domains and timing constraints. Te resulting architecture behaves less like a monolithic computing platform and more like a tightly- coupled distributed system that requires deterministic synchronisation across multiple clock domains. Historically, individual devices were


oſten assigned dedicated timing sources tailored to their specific requirements. While effective in simpler systems, this approach scales poorly as platform complexity increases. Multiple oscillators and clock sources increase component count, consume valuable board area and power, and introduce additional noise sources that can complicate overall timing integrity. More importantly, independently- generated clocks make it increasingly difficult to maintain deterministic timing relationships across interconnected devices and subsystems. Te challenge facing system architects


is no longer simply generating clocks. It is delivering coherent timing across an


www.electronicsworld.co.uk November 2026 23


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44