Frame synchronization: Difference between revisions

Revision as of 00:30, 11 May 2024

Revision as of 20:48, 6 June 2024

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;Framing bit: A common practice in [[telecommunication]]s, for example in [[T-carrier]], is to insert, in a dedicated [[Time-division multiplexing|time slot]] within the frame, a noninformation '''framing bit''' that is used for synchronization of the incoming data with the receiver. In a [[bit stream]], framing bits are predictable (do not carry information), and occur at specified positions in the frame. Correct framing is verified when almost all framing bits (minus a small allowance for transmission errors) have their predicted values.

;Syncword and flag sequence framing: Rather than a single bit, some systems use a multi-bit [[syncword]] in each frame, or a '''flag sequence''' that marks the beginning and end of each frame. [[High-Level Data Link Control]] and similar systems use flag sequences.<ref>{{Cite reportIETF |urlrfc=https://datatracker.ietf.org/doc/rfc1662/1662 |title=PPP in HDLC-like Framing |last=Simpson |first=William A. |date=July 1994 |publisher=Internet Engineering Task Force |issue=RFC 1662}}</ref>

;CRC-based framing: Some telecommunications hardware uses [[CRC-based framing]], where correct framing is verified when almost all frames have valid CRCs.

==Frame synchronizer==