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السؤال 85

Which of the following describes the use of vestigial sideband in analog fast-scan TV transmissions?

  1. The vestigial sideband carries the audio information
  2. The vestigial sideband contains chroma information
  3. Vestigial sideband reduces the bandwidth while increasing the fidelity of low frequency video componentsالإجابة الصحيحة
  4. Vestigial sideband provides high frequency emphasis to sharpen the picture

الشرح

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.

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