Yep, ATSC uses a single data stream across the alloted bandwidth. It is an all-or-nothing system, but it uses Forward Error Correction so if you are getting dropouts you need to look at better reception gear and/or aiming if possible.
The old analogue NTSC system uses the alloted 6MHz of channel bandwidth by chopping it up into specific parts for video and audio, and not only that but a station's own video and audio signals would interfere with each other if they used the same modulation so NTSC was deliberately specified to use AM (Amplitude Modulation) for the video while the audio portion uses FM (Frequency Modulation).
That's why it is possible to receive NTSC analogue audio and/or video separately.
The old analogue NTSC system uses the alloted 6MHz of channel bandwidth by chopping it up into specific parts for video and audio, and not only that but a station's own video and audio signals would interfere with each other if they used the same modulation so NTSC was deliberately specified to use AM (Amplitude Modulation) for the video while the audio portion uses FM (Frequency Modulation).
That's why it is possible to receive NTSC analogue audio and/or video separately.
