2.2 SYSTEM BLOCK DIAGRAM A sample system block diagram for the MT1379 DVD player board design is shown in the following figure:
3. AUDIO OUTPUT
The ZR36768 supports two-channel to eight-channel analog audio output. This version has twochannel output. The ZR36768 also provides digital output in S/PDIF format. The board supports both optical and coaxial SPDIF outputs.
4. AUDIO DACS
The ZR36768 supports several variations of an I2S type bus. The I2S format uses four stereo data lines and three clock lines. The I2S data and clock lines can be connected directly to one or more audio DAC to generate analog audio output. The two-channel DAC is a Cirrus Logic CS4392. The DACs support up to 192kHz sampling rate. The outputs of the DACs are differential, not single ended so a buffering circuit is required. The buffer circuit use a National LM833 op-amp to perform the low-pass filtering and the buffering.
5 .VPU - VIDEO PROCESSING UNIT
The VPU is responsible for all video output processing and timing. It outputs 8 bit (CCIR 656 type) digital interlaced video and separate syncs. It can also output interlaced composite, S- or component analog video, or progressive components analog video. The VPU units have two operating modes: Interlaced when the output is interlaced and Progressive when the output is progressive. A two fields Deinterlacer can be used (as needed) for the decoded image. The VPU has a sync generator and output unit. The sync signals are used by the sync receiver unit to generate all video timing for all other VPU units and timing signals for the CPU and PDU.
