Online Acoustic Wave Sensing for Paperboard Score Quality Control
Inline acoustic wave sensing detects sub-surface paperboard delamination during scoring, stopping un-creased board defects before downstream cartoning line jams.
Phase Velocity Dispersion
Wavefront Propagation
Optical signals experience a non-linear temporal delay when different frequency components of a pulse travel through a material at varying speeds. Phase velocity dispersion describes the mechanism by which the refractive index of a substrate varies according to the wavelength of the light source passing through it. This dependency forces the constituent parts of a signal to spread out in time as they transit a medium.
Material integrity depends upon managing this phenomenon to maintain the fidelity of information transmitted across fibre optic networks.
Pulse Distortion
Digital signals rely on distinct pulses of light to encode binary data accurately. As a signal undergoes phase velocity dispersion, the individual frequencies constituting a single pulse arrive at the detector at disparate intervals. The output signal broadens, which causes the trailing edge of one data pulse to bleed into the leading edge of the subsequent pulse.
High density signal transmission requires precise compensation to mitigate this overlap. Converting operations that utilize laser-based diagnostic tools or high speed machine vision sensors monitor this spectral shift to prevent data corruption during real time quality control. Engineers calibrate the receiver hardware to reassemble the delayed frequency components into their original temporal alignment.
Substrate Specification
Fibre manufacturing processes dictate the limits of signal broadening by adjusting the chemical composition of the glass core. The refractive index profile determines how the light frequency maps to the internal path geometry. Manufacturers apply specific dopants to the silica to tune the dispersion characteristics for standard operating windows.
Tight control over the purity of the raw materials ensures that the variation in velocity remains within the narrow tolerance required for high bandwidth communication. Consistent dispersion profiles allow for predictable performance across long distance cabling installations.