Looking at where the clock flows
Clocking Signal Flows
A master clockat 24.576MHz is used to temporize all the DSP, ADC and DAC. It is the use of a clock external to the DSP thta allows the input to be decoupled from the output so that the DSP does not have to keep to a constant cycle time. The accurancy of this clock determines the accurancy of the 19KHz pilot signal. This has to be held ∓ 2Hz of 19KHz.
The DSP runs at a clock frequency of 4 x 24.576MHz. Like wise a 12.288MHz forms the master clock for both the ADC and the DAC. The ASDC id master to the DSP so the left/Right clock from the ADC triggers sample taking by the DSP. The DAC is Master to the DSP but slave to the clock stream so a 384KHz clock is used to synchronise the DAC sampling.