Analogue and Digital Flashcards
What is meant by the term Bit Rate?
Bit Rate measures the number of samples of a signal taken in a single second, the higher the bit rate the better the quality, but also the higher the bandwidth required for transmission.
What is Bit Depth?
Bit depth is the number of possible states that can be recorded. The lowest bit depth is 2, like a light switch, either on or off, and can be represented with just one binary character, either 0 or 1. To record a bit depth of 4 would require 2 characters:
00 = 0
01 = 1
10 = 2
11 = 3
A bit depth of 8 would require 3 characters and so on.
(Notice the logarithmic relationship here, using exponents of the base 2.)
8 characters gives a bit depth of 256, as used on IP addresses.
Standard Audio CDs use a bit depth of 16, giving 65,536 possible states.
How many characters are needed to provide a bit depth of 256?
8 characters.
What is the advantage of sending digital signals over a long distance, compared to analogue?
As analogue signals have so many possible values, it can be difficult to maintain the quality over long distances. If analogue signals are amplified, then any noise is also amplified, meaning that by the time the signal reaches its destination, the quality could be quite poor.
Digital signals by comparison can be recognised more easily as either on or off, and can simply be regenerated as completely clean new signals before being sent on.
Which value represents On in a digital signal?
On is represented by 1.
