4.3 Basics of Signals and Noise in Communications Systems 4.3.8 Dispersion, jitter, and latency Dispersion, jitter, and latency are actually three different things that can happen to a bit. They are grouped together because each affect the same thing - the timing of a bit. Since you are trying to understand what problems might occur as millions and billions of bits travel on a medium in one second, timing matters a lot.
Dispersion is when the signal broadens in time.
It is caused by the type of media involved. Since you want to send billions of bits per second, you must be careful not to allow the signals to spread out . Dispersion can be fixed by proper cable design, limiting cable lengths, and finding the proper impedance. In optical fibers, dispersion can be controlled by using laser light of a very specific wavelength. For wireless communications, dispersion can be minimized by the frequencies used to transmit.