Editing 8VSB (section)

==Modulation technique==
Vestigial sideband modulation (VSB) is a modulation method which attempts to eliminate the spectral redundancy of [[pulse-amplitude modulation]] (PAM) signals. Modulating a carrier by a real-valued data sequence results in a sum and a difference frequency, resulting in two symmetrical carrier side-bands. The symmetry means that one of the sidebands is redundant, so removing one sideband still allows for demodulation. As filters with zero transition bandwidth cannot be realized, the filtering implemented leaves a vestige of the redundant sideband, hence the name "VSB".