Propagation Delay
Signal timing distortion occurs when differential signals travel across varying dielectric constants within a circuit board substrate. A high-speed signal encounters 1078 glass weave skew when one trace of a pair aligns with the glass bundles of the cloth while the other sits over the resin-rich gaps. This misalignment causes the signals to arrive at the receiver at different times.
Such phase shifts degrade the signal quality in gigabit per second applications where timing margins are narrow.
Glass Construction
Material geometry defines the physical arrangement of the glass yarns within the laminate. The 1078 weave style consists of relatively thin glass bundles spaced loosely compared to heavier or flatter fabrics. This open structure increases the likelihood of a trace running entirely over a resin pocket or a glass bundle.
Designers often rotate the layout or use mechanically spread glass to reduce these localized dielectric variations. Fabrication shops measure the dielectric constant of both the resin and the glass to predict the resulting skew levels.
Phase Stability
Differential performance depends on the consistency of the delay between the two paths. When 1078 glass weave skew exceeds the jitter budget of the interface, bit errors occur frequently. High-frequency signals above 10 GHz are particularly sensitive to these micro-scale variations.
Reliable transmission requires matching the electrical length of the paths within a few picoseconds.
