Which of the following describes the use of vestigial sideband in analog fast-scan TV transmissions?
The vestigial sideband carries the audio information
The vestigial sideband contains chroma information
Vestigial sideband reduces the bandwidth while increasing the fidelity of low frequency video components✓Bonne réponse
Vestigial sideband provides high frequency emphasis to sharpen the picture
Explication
Double sideband AM video would need roughly twice the channel width, but filtering off most of one sideband would also attenuate the low video frequencies that sit closest to the carrier and carry the large-area brightness. Vestigial sideband keeps a vestige of the second sideband next to the carrier, so the low frequency video components survive intact while the channel stays narrow; audio rides on a separate carrier and chroma on the colour subcarrier.