Digital Audio VS Analog Audio

There are both digital and analog audio sources in use today. most of all of us are used to dealing with analog connections for audio, but digital is becoming much more common.

Analog audio sources

Probably one of the analog connections that is easiest to recognize is the set of white and red RCA jacks that we used for so many years on our VCRs, earlier DVD players, camcorders, etcetera. Another really common one is the headphone connection we all use on our MP3 players.  That is another example of an analog audio connection.  As i'm typing this, it's running through my head that I may spark the question "But wait.... aren't MP3s digital?".  The answer to that question is yes, MP3s are digital, but the audio signal being transmitted out of your MP3 player is analog.

What uses digital audio signals then?

There are 3 types of digital audio signals that are the most common at this point.  Interestingly, all 3 of these digital audio formats are used primarily in home theater systems.  One format is found in the HDMI connection.  HDMI is a digital interface that transmits both digital video and digital audio from an AV source to your display (HDTV or HD projector).  The benefit of this system is that it carries both the audio and video signals in a single connection.  The other two formats are used for almost identical purposes.  The first is digital coax, which is a digital signal transmitted over a copper cable with standard RCA ends on it.  This digital connection allows you to be able to transmit multiple audio channels on a single cable, unlike the analog RCA connections.  The other option is the Toslink audio connection.  Toslink is an optical audio connection.  This means that it transmits the audio signal through a fiber optic cable as a series of pulses of light instead of electricity over copper wires.   The fact that the connection is optical makes it unaffected by any electro-magnetic interference and helps to preserve the highest quality audio signal.  Just like with the digitial coax, the Toslink connection can support all your audio channels on a single cable.

How do I communicate between the two formats?

Occasionally you may run into the need to convert from one format to another.  For example, say you have a Blu-Ray player with only digital outputs, but you want to go to an older AV receiver that only has analog inputs.  Don't worry, there's a perfectly simple solution.  What you'll need is a digital to analog audio converter.  This will take as input either the digital coax or the Toslink signal and then output an analog audio signal.  This will allow you to keep using your analog stereo equipment with your digital sources.