All sound is by nature analog. The PC, however, processes sound in
digital format. The key to high quality PC sound is to keep the audio
data digital as long as possible and process it in digital form outside
the interference-laden confines of the PC.
Plantronics' digitally enhanced headsets do precisely this. Sound
exists in analog form only where it absolutely has to be between
the user and the headset module. From there on it is purely digital.
Here is an example:
When you speak into the headset microphone, analog sound is converted
into electrical signals. These analog signals go to the CODEC where
they are converted to digital packets. They're then modified by
the DSP depending on the settings chosen, and placed on the USB
bus where they travel into the computer and are used by the application.
Conversely, audio data sent digitally from the PC travels via the
USB to the headset and are processed by the DSP. The sound data
is then converted back into the analog waves you hear through the
headset speakers.
Contrast this with a conventional analog scenario, where audio
data spends most of its time in analog form. A typical sound card
(which again, resides in an electrically noisy environment) with
a microphone and speakers attached deals with digital data only
between the sound card and the PC. Once the data arrives at the
sound card, after its travel through PC generated noise, it is processed
and transported in analog format.
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