Inside the headend, what are the modulation methods used for video, audio, and color signals?

Inside the headend, what are the modulation methods used for video, audio, and color signals?

• A. Video signals are amplitude modulated, audio signals are frequency modulated, and color signals are amplitude and phase modulated
• B. Video signals are frequency modulated, audio signals are amplitude modulated, and color signals are phase modulated
• C. Video signals are amplitude modulated, audio signals are amplitude modulated, and color signals are frequency modulated
• D. Video signals are phase modulated, audio signals are frequency modulated, and color signals are amplitude modulated

Answer: (A)

In the headend, video is carried by amplitude modulation of the RF carrier (with vestigial sidebands to save bandwidth). The audio path uses frequency modulation on its own subcarrier for good fidelity. The color information travels on a chrominance subcarrier and is encoded by variations in both amplitude and phase, i.e., a combination of amplitude and phase modulation. So the correct description is video as amplitude modulated, audio as frequency modulated, and color signals as modulated in both amplitude and phase. The other options mix up these modulation types or omit the dual modulation used for color.

In the headend, video is carried by amplitude modulation of the RF carrier (with vestigial sidebands to save bandwidth). The audio path uses frequency modulation on its own subcarrier for good fidelity. The color information travels on a chrominance subcarrier and is encoded by variations in both amplitude and phase, i.e., a combination of amplitude and phase modulation. So the correct description is video as amplitude modulated, audio as frequency modulated, and color signals as modulated in both amplitude and phase. The other options mix up these modulation types or omit the dual modulation used for color.