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Frame synchronization is the process of synchronizing display pixel scanning to a synchronization source. When several systems are connected, a synchronization signal is fed from a master system to the other systems in the network, and the displays are synchronized with each other.

While receiving a stream of framed data, frame synchronization or framing is the process by which incoming frame alignment signals (i.e., a distinctive bit sequences or syncwords) are identified (that is, distinguished from data bits), permitting the data bits within the frame to be extracted for decoding or retransmission.

Framing

If the transmission is temporarily interrupted, or a bit slip event occurs, the receiver must re-synchronize.

Frame synchronized PCM stream — telemetry application

The transmitter and the receiver must agree ahead of time on which frame synchronization scheme they will use.

Common frame synchronization schemes are:

Framing bit: A common practice in telecommunications, for example in T-carrier, is to insert, in a dedicated time slot within the frame, a noninformation bit or framing bit that is used for synchronization of the incoming data with the receiver. In a bit stream, framing bits indicate the beginning or end of a frame. They occur at specified positions in the frame, do not carry information, and are usually repetitive.
Syncword framing: Some systems use a special syncword at the beginning of every frame.
CRC-based framing: Some telecommunications hardware uses CRC-based framing.

Frame synchronizer

Television

A frame synchronizer is a device used in live television production to match the timing of an incoming video source to the timing of an existing video system. They are often used to "time in" consumer video equipment to a professional system but can be used to stabilize any video. The frame synchronizer essentially takes a picture of each frame of incoming video and then immediately outputs it with the correct synchronization signals to match an existing video system. A genlock signal is required to provide a means for video synchronizing with the house reference.

Telemetry

PCM stream prior to frame synchronization

In telemetry applications, a frame synchronizer is used to frame-align a serial pulse code-modulated (PCM) binary stream.

File:Commutation.jpg

Different types of commutation within a frame synchronized PCM stream

The frame synchronizer immediately follows the bit synchronizer in most telemetry applications. Without frame synchronization, decommutation is impossible.

The frame synchronization pattern is a known binary pattern which repeats at a regular interval within the PCM stream. The frame synchronizer recognizes this pattern and aligns the data into minor frames or sub-frames. Typically the frame sync pattern is followed by a counter (sub-frame ID) which dictates which minor or sub-frame in the series is being transmitted. This becomes increasingly important in the decommutation stage where all data is deciphered as to what attribute was sampled. Different commutations require a constant awareness of which section of the major frame is being decoded.

References

This article incorporates public domain material from Federal Standard 1037C. General Services Administration. Archived from the original on 2022-01-22. (in support of MIL-STD-188).

Scientific articles

J. L. Massey. "Optimum frame synchronization ". IEEE trans. comm., com-20(2):115-119, April 1972.
R Scholtz. "Frame synchronization techniques", IEEE Transactions on Communications, 1980.
P. Robertson. "Optimal Frame Synchronization for Continuous and Packet Data Transmission", PhD Dissertation, 1995, Fortschrittberichte VDI Reihe 10, Nr. 376 PDF

External links

@@ Line 1: / Line 1: @@
 {{context|date=February 2013}}
 {{expert-subject|1=Video|date=February 2013}}
-Frame synchronization is the process of synchronizing display pixel scanning to a synchronization source. When several systems are connected, a sync signal is fed from a master system to the other systems in the network, and the displays are synchronized with each other.
+'''Frame synchronization''' is the process of synchronizing display pixel scanning to a synchronization source. When several systems are connected, a synchronization signal is fed from a master system to the other systems in the network, and the displays are synchronized with each other.
-While receiving a stream of [[data frame|framed]] [[data]], '''frame synchronization''' or '''framing''' is the process by which incoming frame alignment signals (i.e., a distinctive [[bit]] sequences or [[syncword]]s), are identified (that is, distinguished from data bits), permitting the data bits within the frame to be extracted for decoding or retransmission.
+While receiving a stream of [[data frame|framed]] [[data]], frame synchronization or '''framing''' is the process by which incoming frame alignment signals (i.e., a distinctive [[bit]] sequences or [[syncword]]s) are identified (that is, distinguished from data bits), permitting the data bits within the frame to be extracted for decoding or retransmission.
 == Framing ==
 If the transmission is temporarily interrupted, or a [[bit slip]] event occurs, the receiver must re-synchronize.
 [[Image:Frame Synced Stream.jpg|frame|none|Frame synchronized PCM stream — telemetry application]]
-The transmitter and the receiver must agree ahead of time on which frame synchronization scheme they will use.
+The transmitter and the receiver must agree ahead of time on which frame [[synchronization]] scheme they will use.
 Common frame synchronization schemes are:
-;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 bit or '''framing bit''' that is used for [[synchronization]] of the incoming data with the receiver.  In a [[bit stream]], framing bits indicate the beginning or end of a frame.  They occur at specified positions in the frame, do not carry information, and are usually repetitive.
+;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 bit or '''framing bit''' that is used for synchronization of the incoming data with the receiver. In a [[bit stream]], framing bits indicate the beginning or end of a frame. They occur at specified positions in the frame, do not carry information, and are usually repetitive.
-;Syncword framing:  Some systems use a special [[syncword]] at the beginning of every frame.
+;Syncword framing: Some systems use a special [[syncword]] at the beginning of every frame.
-;CRC-based framing:  Some telecommunications hardware uses [[CRC-based framing]].
+;CRC-based framing: Some telecommunications hardware uses [[CRC-based framing]].
 ==Frame synchronizer==
 ===Television===
 {{further|Time base corrector}}
-A '''frame synchronizer''' is a device used in [[live television]] [[television production|production]] to match the timing of an incoming [[video]] source to the timing of an existing video system.  They are often used to "time in" consumer video equipment to a professional system but can be used to stabilize any video.  The frame synchronizer essentially takes a picture of each [[Film frame|frame]] of incoming video and then immediately outputs it with the correct synchronization signals to match an existing video system.  A [[genlock]] signal is required to provide a means for video synchronizing with the house reference.
+A '''frame synchronizer''' is a device used in [[live television]] [[television production|production]] to match the timing of an incoming [[video]] source to the timing of an existing video system.  They are often used to "time in" consumer video equipment to a professional system but can be used to stabilize any video. The frame synchronizer essentially takes a picture of each [[Film frame|frame]] of incoming video and then immediately outputs it with the correct synchronization signals to match an existing video system.  A [[genlock]] signal is required to provide a means for video synchronizing with the house reference.
 ===Telemetry===
+[[Image:PCM Stream.jpg|frame|none|PCM stream prior to frame synchronization]]
+In [[telemetry]] applications, a ''frame synchronizer'' is used to frame-align a serial pulse code-modulated ([[Pulse-code modulation|PCM]]) binary stream.
-[[Image:PCM Stream.jpg|frame|none|PCM Stream prior to frame synchronization]]
-In [[telemetry]] applications, a ''frame synchronizer'' is used to frame align a serial pulse code modulated ([[Pulse-code modulation|PCM]]) binary stream.
 [[Image:Commutation.jpg|frame|none|Different types of commutation within a frame synchronized PCM stream]]
-The frame synchronizer immediately follows the bit synchronizer in most telemetry applications.  Without frame synchronization [[Decommutator|decommutation]] is impossible.
+The frame synchronizer immediately follows the bit synchronizer in most telemetry applications. Without frame synchronization, [[Decommutator|decommutation]] is impossible.
-[[Image:Frame Synced Stream.jpg|frame|none|Frame synchronized PCM stream]]
+[[Image:Frame Synced Stream.jpg|frame|none|Frame-synchronized PCM stream]]
-The frame syncronisation pattern is a known binary pattern which repeats at a regular interval within the PCM stream.  The frame synchronizer recognizes this pattern and aligns the data into minor frames or sub-frames.  Typically the frame sync pattern is followed by a counter (Sub-Frame ID) which dictates which minor or sub frame in the series is being transmitted.  This becomes increasingly important in the decommutation stage where all data is deciphered as to what attribute was sampled.  Different commutations require a constant awareness of which section of the major frame is being decoded.
+The frame synchronization pattern is a known binary pattern which repeats at a regular interval within the PCM stream. The frame synchronizer recognizes this pattern and aligns the data into minor frames or sub-frames. Typically the frame sync pattern is followed by a counter (sub-frame ID) which dictates which minor or sub-frame in the series is being transmitted.  This becomes increasingly important in the decommutation stage where all data is deciphered as to what attribute was sampled.  Different commutations require a constant awareness of which section of the major frame is being decoded.
 ==See also==
 * [[Asynchronous start-stop]]
 * [[Phase synchronization]]
@@ Line 46: / Line 42: @@
 ==References==
+{{Reflist}}
 {{FS1037C MS188}}
 ===Scientific articles===
 * J. L. Massey. "Optimum frame synchronization ". IEEE trans. comm., com-20(2):115-119, April 1972.
-* R Scholtz. "Frame synchronization techniques", IEEE Transactions on Communications, 1980.
+* R Scholtz. "Frame synchronization techniques", ''IEEE Transactions on Communications'', 1980.
-* P. Robertson. "Optimal Frame Synchronization for Continuous and Packet Data Transmission", PhD Dissertation,
+* P. Robertson. "Optimal Frame Synchronization for Continuous and Packet Data Transmission", PhD Dissertation, 1995, Fortschrittberichte VDI Reihe 10, Nr. 376 [http://www.kn-s.dlr.de/People/Robertson/Papers/diss.pdf PDF]
-, Fortschrittberichte VDI Reihe 10, Nr. 376 [http://www.kn-s.dlr.de/People/Robertson/Papers/diss.pdf PDF]
 ==External links==
 * [http://www.ulyssix.com Telemetry Ground Station Processing Electronics telemetry link]
 * [http://www.algolith.com/products/broadcast/frame-synchronization/index.html Algolith Frame Synchronizer Solutions]