Giovanna Sherlin: 1. Audio and video are added to a television over-the-air signal. The raw signal is called the carrier. When audio and/or video is added, the carrier is said to be modulated.2. With analog TV, the video is formed by varying the output power of the TV transmitter (amplitude modulation), creating analog waveforms that the TV receiver can build into a picture. The audio component is formed by varying the frequency of a portion of the signal (frequency modulation), also creating waveforms that the TV's audio detector can form into sound.3. With digital TV, the modulation for both video and audio is a digital bitstream. The TV receiver separates the video and audio components to create images and sound.Pros of analog: mainly just one: a weak signal is often watchable, just a little snowy. With digital, a weak signal doesn't even show up.Pros of digital: digital transmission has made HD possible, plus it allows for additional standard-def channels to! be transmitted within the same spectrum space as one analog channel. For example, my local PBS station was formerly channel 6. It now broadcasts in HD on 6.1, plus it has separate programming on 6.2 and 6.3.Another significant difference: because of the weak signal issue explained above, many people who got by with simple antennas with analog have found that they must upgrade the antenna system to get all of their digital channels. For example, it's very common that viewers who got by with an indoor antenna (like "rabbit ears") with analog to now need a full size antenna above the roof....Show more
Corrina Faro: digital and analog is the way of MODULATION on transmitter and DETECTION on receiver.analog tv may has SNOW and GHOST.....digital no snow no ghost...picture quality high.if the antenna signal level is not enough for digital tv....its picture fragments in some pieces.
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