Compaq DC7600 HP Compaq dx 7200 and dc7600 Personal Computers, Technical Refer - Page 112

Input/Output Interfaces 5.8.3 HD Audio Codec The HD Audio Codec provides pulse code modulation (PCM) coding and decoding of audio information as well as the selection and/or mixing of analog channels. As shown in Figure 5-13, analog audio from an external microphone, tape, or internal CD can be selected and, if to be recorded (saved) onto a disk drive, routed through an analog-to-digital converter (ADC). The resulting left and right PCM record data are muxed into a time-division-multiplexed (TDM) data stream (SD IN signal) that is routed to the audio controller. Playback (PB) audio takes the reverse path from the audio controller to the audio codec as SD OUT data and is decoded and either routed through an equalizer or applied directly to the digital-to-analog converter (DAC). The codec supports simultaneous record and playback of stereo (left and right) audio. The sampling rate used by the Sample Rate Controllers (SRC) may be set independently for the ADCs and the DAC. The integrated analog mixer provides the computer control-console functionality handling multiple audio inputs. Audio Format Mic Audio In CD Audio In Mux REC Gain ADC w/SRC Audio In Line Audio In PC Beep In REC Mux Gain Mux/Gain Line Audio Out PB Gain HP Audio Out PB Gain ADC w/SRC Audio In SDI HD Audio Interface RST# BCLK SYNC HD Audio Link Bus to/from Audio Controller DAC w/SRC Audio Out SDO NOTE: The audio codec includes two ADCs. However, only one is typcially used. All audio lines represent both left and right channel information. Figure 5-13. ALC260 HD Audio Codec Functional Block Diagram All functions are controlled through index-addressed registers of the codec. 5-32 www.hp.com Technical Reference Guide