When you next see an orange RCA jack labeled "Digital Out," remember: inside that plastic shell, a 24-bit word is being transmitted LSB-first, preceded by a preamble that violates its own encoding rules, hoping that the receiver’s PLL is having a good day.
Even if you transmit 24-bit audio, you still transmit 32 bits per subframe. The lower 8 bits (bits 24–31) are overhead. This is why S/PDIF has a "24-bit payload" but uses a 32-bit slot. 2. The Preamble Trick: No Clock Line Needed S/PDIF uses Bi-Phase Mark Code (BMC) to embed the clock. Each data bit is represented by either one or two transitions. A '0' has a transition at the start of the bit cell; a '1' has an additional transition in the middle. seehd24
A 24-bit signal has a theoretical dynamic range of 144 dB. But S/PDIF's embedded clock recovery (PLL) typically introduces timing jitter of 200–500 ps in consumer gear. That jitter modulates the amplitude of the highest-frequency content, folding into the noise floor at approximately -110 dBFS. In practice, . You get ~20-21 bits of real resolution, plus 3 bits of marketing. When you next see an orange RCA jack