Antex Electronics StudioCard AV Pro, StudioCard 2000, & SC-22 - Manual (Page 114)

A n a l o g A u d i o C h a p t e r 6
Antex Electronics Corporation Antex StudioCard 6-5
Analog Audio Analog audio enters the StudioCard through its four balanced
audio inputs. Each channel’s differential signal is converted to
a single-ended signal by a differential amplifier and then
adjusted in a variable gain stage according to the desired
nominal level of either -10 dBV or +4 dBu. The signal is then
converted to digital by a 20-bit sigma delta analog-to-digital
converter.
Data from each audio input channel is received by the DSP and
routed to one of eight audio device streams. Each audio device
is visible to host applications in the form of a standard
multimedia device. Each device has dedicated buffers that are
sized to accommodate system latencies.
Analog audio for each of the StudioCard’s four output channels
is derived from a mix of up to eight audio devices. The DSP is
responsible for mixing the data from each device stream and
routing the mixed signal to each channel’s 20-bit sigma delta
digital-to-analog converter. The signal is then adjusted in a
variable gain stage according to the desired nominal level of
either -10 dBV or +4 dBu and then converted from single-
ended to differential for balanced line transmission.