Who can help me about GSMK&8PSK

[evolutionfox]

filter bw gmsk

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.

 

[m_llaa]

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

 

[janath]

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.

 

[evolutionfox]

Thanks,but can you give me some detail material?
my mail is hutiening@yahoo.com.cn

 

[safwatonline]

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).

 

[Daniz40]

here is pdf file from where u can find info abt GMSK and PSK

 

[Daniz40]

THis is a book. hope it will help

 

[evolutionfox]

thanks all of you.