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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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190:, every character is, in effect, a syncword, and can be used to achieve character synchronization in an undifferentiated bit stream.
179:" characters in the message‍—‌in effect, every "space" character in the message does double duty as a syncword. For example,
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127:" 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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202:, preamble is a sequence of known bits sent in each frame. It is used for
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142:, or‍—‌in other words‍—‌to "disguise" bytes of data at the
289:"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.
18:"Preamble" to communications message data after a header
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protocol of the 1960s used a minimum of two ASCII "
93:of data, an example of a syncword is 0x0B77 for an
333:(2nd ed.). Taylor & Francis. p. 12.
154:or "octet stuffing", while other systems use
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138:. Various techniques are used to avoid
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134:The syncwords can be seen as a kind of
129:synchronize to the beginning of a frame
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330:Computer communications and networks
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287:Bastian Bloessl; Falko Dressler.
231:Copy protection § Early ages
160:Consistent Overhead Byte Stuffing
371:Packets (information technology)
306:Connectivity Knowledge Platform
1:
219:automatic baud rate detection
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236:Magic number (programming)
47:by indicating the end of
43:is used to synchronize a
188:self-synchronizing code
75:self-synchronizing code
65:wireless communications
327:John R. Freer (1996).
246:Start Frame Delimiter
204:frame synchronization
200:digital communication
140:delimiter collision
212:channel estimation
366:Data transmission
340:978-1-85728-379-2
210:, as well as for
181:CRC-based framing
45:data transmission
25:computer networks
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251:Synchronous idle
241:Out-of-band data
97:encoded stream.
57:reference signal
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361:Synchronization
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276:"USB Protocols"
274:Craig Peacock.
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208:Ethernet frames
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144:data link layer
131:of characters.
102:Ethernet packet
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33:sync character
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302:"BiSync, BSC"
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37:sync sequence
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310:. Retrieved
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256:Pilot signal
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166:Alternatives
152:bit stuffing
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89:receiving a
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71:Prefix codes
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206:such as in
156:ASCII armor
355:Categories
262:References
91:bit stream
308:. Made IT
136:delimiter
225:See also
194:Preamble
162:(COBS).
81:Examples
61:midamble
53:sequence
41:preamble
29:syncword
312:July 5,
291:. 2018.
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173:FSK441
121:Bisync
85:In an
49:header
186:In a
177:space
150:uses
27:, a
335:ISBN
314:2011
148:HDLC
119:The
108:All
95:AC-3
198:In
158:or
125:SYN
110:USB
100:An
63:in
59:or
39:or
23:In
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