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Who can help me about GSMK&8PSK

 
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evolutionfox



Joined: 24 May 2006
Posts: 9
Post02 Jun 2006 4:02   Who can help me about GSMK&8PSK
Who can supply me some material about GSMK&8PSK modulation? I am just getting in touch with GSM&EDGE mobile design. If somebody have mobile signal process material,please also send to me. My e-mail:hutiening(at)yahoo.com
You also can advise me some good books that you think.
Thanks for your help.
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m_llaa



Joined: 12 Mar 2006
Posts: 272
Helped: 23
Location: My Love Iran
Post02 Jun 2006 10:24   Re: Who can help me about GSMK&8PSK
Hi
it is GMSK (Gaussian Minimum Shift Keying) not GSMK
it is a modulation that used in GSM. it is proper bandwidth for GSM
but in (8)PSK (Phase Shift Keying) u can transmit signals with constant amplitude and constant energy, your data information is in the phase of the signals.
8PSK has 8 different phase
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janath



Joined: 21 May 2006
Posts: 33
Helped: 4
Post02 Jun 2006 18:23   Re: Who can help me about GSMK&8PSK
GMSK is modulation schme with memory, that will allow to reduce the outof band radiation. This is due to the frequncy shaping pulse is a gaussian one. This is a binary modulation scheme.


8PSK is a memory less modulation scheme where you map 3 bits into one of the 8 points on a circle.
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evolutionfox



Joined: 24 May 2006
Posts: 9
Post03 Jun 2006 3:38   Who can help me about GSMK&8PSK
Thanks,but can you give me some detail material?
my mail is hutiening(at)yahoo.com.cn
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safwatonline



Joined: 19 Nov 2005
Posts: 1352
Helped: 164
Location: EGYPT
Post03 Jun 2006 11:10   Re: Who can help me about GSMK&8PSK
m_llaa wrote:
Hi
it is GMSK (Gaussian Minimum Shift Keying) not GSMK
it is a modulation that used in GSM. it is proper bandwidth for GSM
but in (8)PSK (Phase Shift Keying) u can transmit signals with constant amplitude and constant energy, your data information is in the phase of the signals.
8PSK has 8 different phase

actually in 8PSK the amplitude is not constant. u have a phase shift of 45 degrees between each symbol , so u will get diffrent amplitude ,(i.e. Asin(n*PI/4) >> gives diffrent amp. for diffrent n).

about GMSK it is MSK"minimum shift keying"+gaussian filter >> minimum shift keying is some kind of binary FSK where two carriers represent two symbels and the minimum notation is due two the distance "band" between the two carriers are chosen so that they are minimum while still having continous phase and NO ISI.
the gaussian filter is added before the MSK modulator to decrease the band width of input signal spectrum which make the total rate of the signal after GMSK < that of MSK. note that this filter although gives lower BW req. it shouldnt be increase so that not to suffer from interference (i.e. the eyediagram close as the Gaussian filter BW dec.)
there is some factor called BT(bw interval) which represent a figure of merit showing both the BW and interference .(BT=0.3 for GSM).
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Daniz40



Joined: 12 Jan 2006
Posts: 106
Helped: 3
Location: Islamabad
Post03 Jun 2006 23:12   Re: Who can help me about GSMK&8PSK
here is pdf file from where u can find info abt GMSK and PSK

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Daniz40



Joined: 12 Jan 2006
Posts: 106
Helped: 3
Location: Islamabad
Post03 Jun 2006 23:21   Re: Who can help me about GSMK&8PSK
THis is a book. hope it will help

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evolutionfox



Joined: 24 May 2006
Posts: 9
Post05 Jun 2006 4:58   Who can help me about GSMK&8PSK
thanks all of you.
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