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8 audio subsystem – HP DC5850 User Manual

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Technical Reference Guide

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5-13

Input/Output Interfaces

5.8 Audio

Subsystem

These systems use the HD audio controller of the SB700 component to access and control an
Analog Devices AD1884A 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 5-8. All control functions such as volume, audio source selection,
and sampling rate are controlled through software through the HD Audio Interface of the SB700
component. Control data and digital audio streams (record and playback) are transferred between
the SB700 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.

Figure 5-8. Audio Subsystem Functional Block Diagram

SB700

HD Audio

Interface

Headphone

Mic In

Audio (L/R)

HD Audio

Codec

AD1884A

Speaker

Audio (mono)

Header

Header

Rear Panel

NOTES:

L/R = Separate left and right channels (stereo). L+R = Combined left and right channels (mono).

P23

P6

Audio

Amp

HD Audio I/F

Front Panel

Line In [1]

Headphones Out

Front Panel

Mic Audio (L/R)

[1] Can be re-configured as Microphone In

PC Beep

Header

P23

Out (L/R)

Line Audio

Line Out

Line Audio (L/R)

Rear Panel