Q We have a TV in the basement that gets its signal digitally from Comcast. There is a TV set upstairs that also receives its signal from Comcast, but not digitally. When they are both on the same channel, the sound coming from the TV upstairs seems to be over five seconds ahead of the one in the basement. We can hear laughter, applause and dialogue, from the upstairs TV before it's on the downstairs one. Why?
A The difference in the signal delivery between the two TVs comes down to digital processing, said Dave Nyberg, senior corporate affairs manager of Comcast, St. Paul.
He explained it this way:
The television signal that comes into your home from Comcast is in both analog and digital format, with analog just slightly ahead of digital.
In your case, it appears you have two analog TV sets. The one upstairs has the cable plugged directly into the TV set. You are watching TV in analog form.
The downstairs TV has the digital set-top box (converter) provided by Comcast, and the cable is plugged into that box. The box is plugged into the TV. You are watching the digital signal on that TV.
Because of digital processing at the master control facility, the digital signal comes into the house three to four seconds behind the analog signal.
That's why the picture and sound with analog is a bit ahead of the digital picture and sound.
