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rag_perfect
Joined: 01 Sep 2005
Posts: 150
Helped: 7
Location: India
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 26 Dec 2007 12:18 manchester encoding clock recovery |
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| Can anybody tell me plz : what is the need of clock recovery in digital communication?? how randomization process is helpful in clock recovery and spectral shaping ???
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STOYANOV
Joined: 26 Jan 2002
Posts: 41
Helped: 4
Location: Sofia, Bulgaria
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26 Dec 2007 15:07 clock recovery of manchester data |
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Wow..
Search the forum for "Digital communication receivers" , Meyr . Read it.
Good luck!
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master_picengineer
Joined: 03 Sep 2007
Posts: 1050
Helped: 62
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26 Dec 2007 16:05 clock recovery manchester encoding |
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| rag_perfect wrote: |
| Can anybody tell me plz : what is the need of clock recovery in digital communication????? |
Clock recovery is necessary to synchronize the a receiver with the transceiver. It consist in regenerating the clock from the incoming data. Generaly it is used in serial data reception.
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rag_perfect
Joined: 01 Sep 2005
Posts: 150
Helped: 7
Location: India
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28 Dec 2007 4:59 recovering clock from manchester encoding |
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Thankx Master...
but still i m unaware :how randomization process is helpful in clock recovery and spectral shaping ???
can anybody has the concept??? Digital reciever book by meyr is also silent regarding this...
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Google
AdSense
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28 Dec 2007 4:59 Ads |
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A.Anand Srinivasan
Joined: 15 Oct 2005
Posts: 1792
Helped: 216
Location: India
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28 Dec 2007 8:33 clock recovery manchester |
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| randomization process is not generally carried perfectly random... they have their own algorithm such that they avoid continuous occurence of 0 or 1 which may lead to loss of synchronisation...
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master_picengineer
Joined: 03 Sep 2007
Posts: 1050
Helped: 62
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28 Dec 2007 10:11 clock recovery + digital communication |
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| rag_perfect wrote: |
Thankx Master...
but still i m unaware :how randomization process is helpful in clock recovery and spectral shaping ???
can anybody has the concept??? Digital reciever book by meyr is also silent regarding this... |
Hi,
In fact it is not 100 % a randon process. All the data rise/fall transition represent a good information for synchronization. The Manchester encoding for exemple enable a very easy recovery. It become a problem when the data sent is for exemple a set of zeros (000000) or one (1111111) in this case the data doesn't change and there is no transition. For this reson we use that we call the technique of bit stuffing. There is anoter techniques such as the 8/10 bit encoding.
In addition don't forget that the receiver uses a PLL to generate it's local clock using as reference the data transistions.
For additional informations google it using the highligthed bold technical terms.
Reagards,
Master_PicEngineer.
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