Transmission of Digital Sound

When one is sending signals from one piece of digital equipment to another, many problems can be encountered. There is always the fallback position of connecting the analog output of one digital machine to the analog output of one digital machine to the analog input of another digital machine. A copy made in this manner will still sound very clean. But often in real-world work, several generations of copies must be made. If the signal is converted to the analog domain for every copy, unacceptable amounts of noise are gradually introduced.
One problem in connecting digital equipment is that there are several standard combinations of sample rate, number of channels, bit and byte order, and number of bits per channel used in digital audio recording. Some are intended for professional recording studios, other strictly for consumers, and some are called “semiprofessional.” For example, the compact disc nominally stores stereo 16-bit signals at a 44.1-kHz sample rate; this consumer format is acceptable for semiprofessional use. Another format is the Digital Compact Cassette (DCC), which uses a different form of encoding, with sample rates of 32, 44.1, and 48 kHz.
Other kinds of problems occur in recording studios, for example, where equipment with noisy fans must be isolated from the recording studio itself. A digital signal can degrade when transmitted over some kinds of long cables.
To solve the problem of differing sample rates, one uses a sample-rate converter. This process can also introduce subtle amounts of noise if the implementation is not handled properly. Chips have been introduced recently to simplify implementation.