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mobile communication: Working of CDMA

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Enter your search terms. Saturday, February 16, 2008. The following steps are generally performed in the process of CDMA technique:-. Both the senders spread their signals using their key as chipping sequence (the term spreading here refers to the simple multiplication. This is the way in which one CDMA technique is to be performed ,this example involved several simplifications. Subscribe to: Post Comments (Atom). Advanced frequency shift keying(AFSK). View my complete profile.

mobile-communications-info.blogspot.com

mobile communication: Frequency shift keying(FSK)

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Enter your search terms. Saturday, February 9, 2008. Modulation scheme often used for wireless transmission is frequency shift keying(FSK). The simplest form of FSK ,also called binary fsk(BFSK). Can be used .Sudden changes in phase cause high frequencies ,which is an undesired side - effect. It has a wide sinusoidal graph in it. Subscribe to: Post Comments (Atom). Advanced frequency shift keying(AFSK). View my complete profile.

mobile-communications-info.blogspot.com

mobile communication: Cellular systems

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Enter your search terms. Friday, February 22, 2008. Cellular systems for mobile communications implement using SDM. Each transmitter is called base station. Covers a certain area of cell. Cell radii can vary from tens of meters in buildings,100 mtrs in cities ,upto some kilometers in the country side. The shape of cells are never perfect circles or hexagons ,. But depend on envoirnment(buildings,mountains,valleys,etc), on weather conditions. Sometimes on system -load. Less transmission power :-. Having l...

mobile-communications-info.blogspot.com

mobile communication: CDMA technique

http://mobile-communications-info.blogspot.com/2008/02/cdma-technique.html

Enter your search terms. Wednesday, February 13, 2008. Finally ,codes with certain characterstics can be applied to the transmission to enable the use of code division multiplexing (CDM).Code division multiplexing access(cdma). Systems use exactly these codes to seperate different users in code space and to enable acess to a shared medium without interferances .The main problem is how to find good codes and how to seperate the signal from noise generated by other signals and the envoirnment.

mobile-communications-info.blogspot.com

mobile communication: December 2007

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Enter your search terms. Saturday, December 29, 2007. Mobile and wireless devices. Even though many mobile and wireless devices are available ,there will be many more in future.There is no precise classification of these devices like the shape,size ,body.etc.the list of followin device according to there grades.like sensors,embedded controlers,pagers,etc. Monday, December 17, 2007. In 1989, GSM responsibility was transferred to the (ETSI) and phase I of the GSM specifications were published in 1990. ...

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mobile communication: Multi-carrier modulation

http://mobile-communications-info.blogspot.com/2008/02/multi-carrier-modulation.html

Enter your search terms. Wednesday, February 13, 2008. Special modulation scheme that stands some what apart from others are multi-carrier modulation scheme(MCM),orthogonal frequency division multiplexing (OFDM)or coded OFDM (COFDM). In this there is actually the superposition of orthogonal frequencies.The maximum of one subcarrier frequency appers exactly ata frequency where all other sub-carriers are equal to zero. Subscribe to: Post Comments (Atom). Advanced frequency shift keying(AFSK).

mobile-communications-info.blogspot.com

mobile communication: Phase shift keying(PSK)

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Enter your search terms. Saturday, February 9, 2008. Finally , phase shift keying (psk). To receive the signal correctly, the receiver must synchronous in frequently and phase with transmitter. Subscribe to: Post Comments (Atom). Advanced frequency shift keying(AFSK). View my complete profile.

mobile-communications-info.blogspot.com

mobile communication: Advanced frequency shift keying(AFSK)

http://mobile-communications-info.blogspot.com/2008/02/advanced-frequency-shift-keyingafsk.html

Enter your search terms. Saturday, February 9, 2008. Advanced frequency shift keying(AFSK). A famous scheme used in many wireless systems is minimum shift keying (MSK). MSK is basically BFSK without abrupt phase changes. Ie it belongs to CPM schemes .In this data bits are first seperated into even and odd bits ,the duration of each bit being doubled.This scheme also uses two frequencies :f1- lower frequency and f2- higher frequency,the higher frequency is twice that of higher frequency,f2= 2 f1.

mobile-communications-info.blogspot.com

mobile communication: January 2008

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Enter your search terms. Wednesday, January 30, 2008. How modulation is done? It consists of a radio transmitter for digital data .The first step is the digital modulation of data into analog baseband signal according to one of the schemes presented in the following.The analog modulation then shifts the center frequency of analog signal up to the radio carrier .This signal is then transmitted via the antenna . The model actually consist of digital modualtion box and analog modulation box. As for digital ...

mobile-communications-info.blogspot.com

mobile communication: February 2008

http://mobile-communications-info.blogspot.com/2008_02_01_archive.html

Enter your search terms. Friday, February 22, 2008. Cellular systems for mobile communications implement using SDM. Each transmitter is called base station. Covers a certain area of cell. Cell radii can vary from tens of meters in buildings,100 mtrs in cities ,upto some kilometers in the country side. The shape of cells are never perfect circles or hexagons ,. But depend on envoirnment(buildings,mountains,valleys,etc), on weather conditions. Sometimes on system -load. Less transmission power :-. Having l...