Conversely, if a pulse travels through an anomalously ( negatively ) dispersive medium, high frequency components travel faster than the lower ones, and the pulse becomes " negatively chirped ", or " down-chirped ", decreasing in frequency with time.
12.
With \ xi the spatial coordinate and \ tau the temporal coordinate . \ psi ( \ xi, \ tau ) being the dispersion is anomalous and the nonlinearity is self-focusing ( note that similar results could be obtained for a normally dispersive medium combined with a defocusing nonlinearity ).
13.
The total network bandwidth depends on how dispersive the medium is ( more dispersive medium generally has better total bandwidth because it minimises interference ), how many frequencies are available, how noisy those frequencies are, how many aerials are used and whether a directional antenna is in use, whether nodes employ power control and so on.
14.
The work he had done assisting Kramers in the previous year now gave him an important clue about how to model what happened to excited hydrogen gas when it radiated light and what happened when incoming radiation of one frequency excited atoms in a dispersive medium and then the energy delivered by the incoming light was re-radiated sometimes at the original frequency but often at two lower frequencies the sum of which equalled the original frequency.
