Digital signal
A digital signal is a type of analog signal that is a representation of a sequence of discrete values (a quantified signal, for example of an arbitrary bit stream, or of a digitized (sampled and analog-to-digital converted) analog signal.
Description
Digital signals are often electronic, but may be optical.
Digital signals are present in all digital electronics, notably computing equipment and telecommunications.
Although digital signals are strictly a subset of analog signals, they are usually treated as separate things.
As a rule of thumb, a signal may be referred to as digital if system noise is never large enough to change the quantification; whereas with analog signals noise always degrades the operation (for example the output from a modem is normally considered an analog signal).
However, even with systems normally considered fully digital, during transitions, noise can become important -- metastability is one manifestation of this.
See also
TO DO: cross-reference
External links
- Digital signal @ Wikipedia
