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ALOHA Cabled Observatory |
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Aloha Cabled Observatory Engineering Documentation 24 bit A/D Converter
24 Bit ADC The 24 bit ADC is a Cirrus Logic CS5381 (Data Sheet). This IC produces a 64-bit data frame 32 bits each for the left and right channels. Since the data are actually 24 bits, 8 bits of each channel are null. The right channel null bits are replaced by the Manchester encoder (5) as the sync, embedded RS232, and status bits. When used in conjunction with the 24-bit DAC, the CS43122 (Data Sheet) on the shore, the transmission integrity is fully validated. It is incorporated the design of the Cirrus Logic chips to “shut down” the audio if there are transmission bit errors. In other words, the DAC chip decodes a correct frame of data or nothing. The 64-bit frame must be 100% correct or the output is muted. The CS43122 has a mute status bit available that could be used to monitor telemetry between the ADC and DAC.
Rev: 08/10/2007
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