Audio Subsystem; Audio Subsystem (5.9) - HP Compaq dc7800 Series Technical Reference Manual

5.9 Audio Subsystem

These systems use the HD audio controller of the 82801 component to access and control an
Analog Devices AD1884 HD Audio Codec, which provides 2-channel high definition
analog-to-digital (ADC) and digital-to-analog (DAC) conversions. A block diagram of the audio
subsystem is shown in Figure 5-9. All control functions such as volume, audio source selection,
and sampling rate are controlled through software through the HD Audio Interface of the 82801
ICH component. Control data and digital audio streams (record and playback) are transferred
between the ICH and the Audio Codec over the HD Audio Interface. The codec's speaker output
is applied to a 1.5-watt amplifier that drives the internal speaker. A device plugged into the
Headphone jack or the line input jack is sensed by the system, which will inhibit the Speaker
Audio signal.
These systems provide the following analog interfaces for external audio devices:
Microphone In—This input uses a three-conductor 1/8-inch mini-jack that accepts a stereo
microphone.
Line In—This input uses a three-conductor (stereo) 1/8-inch mini-jack designed for connection
of a high-impedance audio source such as a tape deck. This jack can be re-tasked to a
Microphone In function.
Headphones Out—This input uses a three-conductor (stereo) 1/8-inch mini-jack that is
designed for connecting a set of 32-ohm (nom.) stereo headphones. Plugging into the
Headphones jack mutes the signal to the internal speaker and the Line Out jack as well.
Line Out—This output uses a three-conductor (stereo) 1/8-inch mini-jack for connecting left
and right channel line-level signals. Typical connections include a tape recorder's Line In
(Record In) jacks, an amplifier's Line In jacks, or to powered speakers that contain amplifiers.
Front Panel
Mic In
Rear Panel
Line In [1]
NOTES:
L/R = Separate left and right channels (stereo). L+R = Combined left and right channels (mono).
[1] Can be re-configured as Microphone In
Figure 5-9. Audio Subsystem Functional Block Diagram
Technical Reference Guide
PC Beep
82801 ICH
HD Audio I/F
HD Audio
Interface
Header
P23
Mic Audio (L/R)
AD1884
HD Audio
Line Audio (L/R)
Codec
www.hp.com
Speaker
Audio
Audio (mono)
Amp
Header
P23
Headphone
Audio (L/R)
Front Panel
Headphones Out
Line Audio
Out (L/R)
Rear Panel
Line Out
Input/Output Interfaces
Header
P6
5-13