Digital process must be synchronized with the help of a clock

Jitter

A fluctuation of the clock (Jitter) can lead to an irregular sampling (A to D, D to D or D to A) and thus to a signal distortion.

In the case of severely disturbed clock signals, the edge can no longer be reliably detected and incorrectly interpreted bit patterns occur.

To guarantee a correct connection of digital components, there must be a central clock generator. A digital system must have a clock master. Optionally, almost any number of clocks (slaves) can be used

<aside> 📎 NOTICE

In a digital composite (unless a dedicated clock generator is used), the most important converter should always be used as master. When recording, this is the A/D converter, when mixing or digitally producing it is the D/A converter

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Wordclock

The word clock has exactly the period of a sample at a given sampling rate. Transmission is via a 75Ohm BNC cable. At the last device of the chain, the signal must be terminated via a 75Ohm resistor, otherwise the signal can be reflected back. Word Clock Inputs and Outputs are mostly found at more professional devices.

Interface connections

Pulse-code modulation (PCM) is a method used to digitally represent sampled analog signals. It is the standard form of digital audio in computers, compact discs, digital telephony and other digital audio applications. In a PCM stream, the amplitude of the analog signal is sampled at uniform intervals, and each sample is quantized to the nearest value within a range of digital steps.

AES3 (AES/EBU) and AES3id - Short and Long Distances

(Audio Engineering Society/European Broadcasting Union) A professional serial interface for transferring digital audio from CD and DVD players to amplifiers and TVs. AES/EBU is typically used to transmit PCM and Dolby Digital 5.1, but is not tied to any sampling rate or audio standard.

• AES3 uses 110 ohm shielded twisted pair (STP) cable with XLR connectors up to a distance of 100 meters. (balanced)
• AES3id uses 75 ohm coaxial cable and BNC connectors for up to 1,000 meters. (unbalanced)

<aside> 📎 "Unbalanced" coax is better for long distances than "balanced" twisted pairs.

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S/PDIF

(Sony/Philips Digital InterFace) A serial interface for transferring digital audio from CD and DVD players to amplifiers and TVs. S/PDIF is typically used to transmit PCM and Dolby Digital 5.1, but it is not tied to any sampling rate or audio standard.

S/PDIF uses unbalanced 75 ohm coaxial cable up to 10 meters with RCA connectors or optical fiber terminated with a TOSLINK (Toshiba link) connector.