HP dc7800 manual Audio Subsystem Functional Block Diagram

Input/Output Interfaces

5.9Audio 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]

				PC Beep
82801 ICH
		HD Audio		HD Audio I/F
		Interface							Header
						Speaker			P6
								Audio
		Header				Audio (mono)		Amp
	Mic Audio (L/R)		P23
					AD1884	Header
						Headphone	P23
					HD Audio
	Line Audio (L/R)					Audio (L/R)			Front Panel
					Codec
						Line Audio			Headphones Out
						Out (L/R)			Rear Panel
									Line Out

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

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