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A receiver uses a physical layer preamble, also called a physical layer training sequence, to synchronize on the signal by estimating frequency and clock offsets. Some documentation uses "preamble" to refer to a signal used to announce a transmission, to wake-up receivers in a low-power mode. While
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In some communication systems, a receiver can achieve character synchronization from an undifferentiated bit stream, or start-of-header synchronization from a byte stream, without the overhead of an explicit syncword. For example, the
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some systems use exactly the same signal for both physical-layer training and wake-up functions, others use 2 different signals at 2 different times for these 2 functions, or have only one or the other of these signals.
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with the
Ethernet preamble, 56 bits of alternating 1 and 0 bits, allowing the receiver to synchronize its clock to the transmitter, followed by a one-octet start frame delimiter byte and then the header.
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packets begin with a sync field (8 bits long at low speed, 32 bits long at high speed) used to synchronize the receiver's clock to the transmitter's clock.
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201:, every character is, in effect, a syncword, and can be used to achieve character synchronization in an undifferentiated bit stream.
190:" characters in the message‍—‌in effect, every "space" character in the message does double duty as a syncword. For example,
138:" characters (0x16…0x16) to achieve character synchronization in an undifferentiated bit stream, then other special characters to
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allow unambiguous identification of synchronization sequences and may serve as
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that might otherwise be incorrectly recognized as the syncword. For example,
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213:, preamble is a sequence of known bits sent in each frame. It is used for
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153:, or‍—‌in other words‍—‌to "disguise" bytes of data at the
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300:"mSync: Physical Layer Frame Synchronization Without Preamble Symbols"
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protocol achieves character synchronization by synchronizing on any "
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In
Ethernet and other protocols, the preamble can also be used for
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of data used to identify the start of a frame, and is also called
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information and the start of data. The syncword is a known
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achieves character and start-of-header synchronization.
29:"Preamble" to communications message data after a header
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protocol of the 1960s used a minimum of two ASCII "
104:of data, an example of a syncword is 0x0B77 for an
344:(2nd ed.). Taylor & Francis. p. 12.
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165:or "octet stuffing", while other systems use
149:. Various techniques are used to avoid
145:The syncwords can be seen as a kind of
140:synchronize to the beginning of a frame
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341:Computer communications and networks
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298:Bastian Bloessl; Falko Dressler.
242:Copy protection § Early ages
171:Consistent Overhead Byte Stuffing
382:Packets (information technology)
317:Connectivity Knowledge Platform
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230:automatic baud rate detection
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247:Magic number (programming)
58:by indicating the end of
54:is used to synchronize a
18:Preamble (communication)
199:self-synchronizing code
86:self-synchronizing code
76:wireless communications
338:John R. Freer (1996).
257:Start Frame Delimiter
215:frame synchronization
211:digital communication
151:delimiter collision
223:channel estimation
377:Data transmission
351:978-1-85728-379-2
221:, as well as for
192:CRC-based framing
56:data transmission
36:computer networks
16:(Redirected from
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262:Synchronous idle
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108:encoded stream.
68:reference signal
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372:Synchronization
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287:"USB Protocols"
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219:Ethernet frames
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155:data link layer
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321:. Retrieved
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267:Pilot signal
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177:Alternatives
163:bit stuffing
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100:receiving a
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82:Prefix codes
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217:such as in
167:ASCII armor
366:Categories
273:References
102:bit stream
319:. Made IT
147:delimiter
236:See also
205:Preamble
173:(COBS).
92:Examples
72:midamble
64:sequence
52:preamble
40:syncword
323:July 5,
302:. 2018.
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184:FSK441
132:Bisync
96:In an
60:header
197:In a
188:space
161:uses
38:, a
346:ISBN
325:2011
159:HDLC
130:The
119:All
106:AC-3
209:In
169:or
136:SYN
121:USB
111:An
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