Preamble

A preamble is an introductory and expressionary statement in a document that explains the document's purpose and underlying philosophy. When applied to the opening paragraphs of a statute, it may recite historical facts pertinent to the subject of the statute. It is distinct from the long title or enacting formula of a law.

Legal effect

While preambles may be regarded as unimportant introductory matter, their words may have effects that may not have been foreseen by their drafters.

In Canada, the preamble to the Constitution Act, 1867 was cited by the Supreme Court of Canada in the Provincial Judges Reference, to increase guarantees to judicial independence. In India, the Supreme Court frequently rules unconstitutional amendments which violate the Basic Structure of the Constitution, especially its Preamble. The Bosnian Constitutional Court, particularly citing the case law of the Supreme Court of Canada, also declared that the provisions of the preamble of the Bosnian Constitution are invested with a normative force thereby serving as a sound standard of judicial review for the Constitutional Court.

Syncword

In computer networks, a syncword, sync character, sync sequence or preamble is used to synchronize a data transmission by indicating the end of header information and the start of data. The syncword is a known sequence of data used to identify the start of a frame, and is also called reference signal or midamble in wireless communications.

Prefix codes allow unambiguous identification of synchronization sequences and may serve as self-synchronizing code.

Examples

In an audio receiver receiving a bit stream of data, an example of a syncword is 0x0B77 for an AC-3 encoded stream. The Bisync protocol of the 1960s used a minimum of two ASCII "SYN" characters (0x16…0x16) to achieve character synchronization in an undifferentiated bit stream, then other special characters to synchronize to the beginning of a frame of characters.

The syncwords can be seen as a kind of delimiter. Various techniques are used to avoid delimiter collision, or—​​in other words—​​to "disguise" bytes of data at the data link layer that might otherwise be incorrectly recognized as the syncword. For example, HDLC uses bit stuffing or "octet stuffing", while other systems use ASCII armor or Consistent Overhead Byte Stuffing (COBS).

Preamble (anthem)

Preamble was the first national anthem of the Federated States of Micronesia. It was adopted in 1979 and replaced in 1991 by Patriots of Micronesia.

The title refers to the preamble of Micronesia's freshly ratified constitution, from which the lyrics are largely derived.

Lyrics

External links