The difference between analog and digital can best be described in terms of an audio recording. An analog recording is a recording of the actual sound wave. When you play this recording back, you are listening to a true representation of the original sound. That sound recording can be converted to digital. A computer or other device will take “snapshots “in time up and down the curves of the analog wave and convert this data to numbers. Imagine that the sine wave on the right has little dots along the wave. These dots can represent moments in time that the digital sampler picks up. There can be an infinite number of dots. The more snapshots that are taken, the more accurate a duplication of the original recording will be. For example, say you have a 5 minute song recorded on a tape. A sampler; which is a device that converts from analog to digital could take 100 different snapshots to produce a recording that vaguely sounds like the original. This sampler could take 1000 snapshots to produce a sound much closer to the original.
Many audiophiles prefer to listen to vinyl records rather than DVD’s because records are an actual representation of the waves and they feel that there is a certain something missing from a CD, however, beyond a certain number of snapshots, the human brain can’t detect the difference between an actual recording and a digital version. To give you an idea of a digital sound that only has a few snapshots of the actual waves, think of Cher’s song Believe. When you hear that weird sound effect in her voice, you are hearing a poor digital quality; albeit to achieve a cool effect.