Figure 6.2 presents an overview of the encoding system. There are two domains within
the encoder in which a set of frequencies is listed: the source encoding domain and the
channel encoding domain. The source encoding domain, schematically represented by
the audio, video, and transport encoders, uses a family of frequencies based on a clock
of 27 MHz. A clock is used to generate a sample of 42 bits, which is divided into two
elements defined by the specification MPEG-2