Mobile Phone Functions

There are three major sections inside a mobile phone
· Power Section 
· Radio Section 
· Computer Section 

Power Section:

A power section deals with power related tasks such as power distribution or charging the battery so this section can be divided into two sub sections like.

· Power Distribution 

A power distribution section
is built around an "power IC" it takes 3.6V power from battery and regulates its power and then distributes to the other components used in mobile phone circuit. in some mobile phones tech "RF Power amplifier" uses more Power than provided bye mobile phone's battery .i.e. 4.7 V or 5.6 V in some phones. the power Ic with a power boaster coil is used to increase voltages. so we can say that power IC is used to provide power to other components how much they needed. either less than battery voltage or more than it.

· Charging Section 

Acharging section works for battery charging purposes.it is often consists a fuse, a coil, a protecting diode, a filter capacitor and charging IC and some other discreet. the charging section helps battery
to be charged when it needs and when battery is charged, charging IC reads its state of charge and feels it full charged and then disconnects charging from it.

Radio Section:
A radio section has basically a set of four main functions.wich are.
· Band Switching 
· RF Power Amplification 
· Transmitter 
· Receiver 

Band Switching:
In the modern mobile phone communication techniques. the frequency of mobile phone communication is divided into three bands 
· GSM (operates on 900 MHz) 
· DCS (operates on 1800 MHz) 
· PCS (operates on 1900 MHz) 

thethird band is used only in USA whereas the first two bands are used in the rest of the world. band switching is done bye a "ceramic antenna switch" it reads from the radiation dispersed in the air and then switches to the appropriate band. in the very first phase of mobile phones there were single band handsets which operated on single frequency band but now a days all the handsets are dual band or tri
band in operation.  

RF Power Amplifier
RF power amplifier is often called as ".PA" or"Transmitter" its functions is to amplify or boast the power which is being transmitted to air, so may it would be able to communicate with long distances. a typical .PA can amplify rf power up to 0.6W or 600mW. This amount of rf power is sufficient to communicate nearly 20 to 25 kilometers in open area, but all the PA's are controlled by there rf signal processor, so if we are near our cell base tower the PA of our phone will transmit low power but if we are far away it will produce its maximum power.

Transmitting
A mobile phone's rf section is basically built around an rf IC which is often called rf signal processor whereas in nokia it is called hagar IC in some hand sets and in some hand sets it is called Mjoelner. irrespectively of the brands and verity of names we call it rf signal processor. this IC works as transmitter and receiver as well. working as transmitter it takes instructions from phone's computer and also takes audio data from audio section and creates radio waves then mixes audio data to its radio waves according to the instructions given by computer section. this mixer of audio and radio is sent to PA to amplify its strength

Reciever
A reciver section for rf waves is built in rf IC, as it is said that this IC works for dual purposes first transmitting and section recieving. in the recieving section of mobile phones a radio signal is gather from ceramic antenna switch and then it is filtered and sent to rf IC to further process. in rf IC signal is detected and then rectified for audio and data which is sent to audio IC or computer section. 

Computer Section:
A computer section in mobile phone consists of two main functions
· CPU(central processing unit) 
· Memory (RAM, FLASH, COMBO CHIP) 

CPU: 
A CPU is used in mobile phones as a central processing arithematic or controler. the cpu controls various functions in mobile phones like signal, display, sound converting(DSP), charging, power on, rf channel controler, rf tx power conroller, LEDs, vibrator, data processing, data storing etc. so we can say that if a cpu is damaged in any mobile phone it cannot be repaired unless the CPU is not replaced but this type of fault is not even seen to me ever either memory chips can be damaged. in brand Nokia CPU is named with two different words (MAD or UPP)

Memory:
there are two main types of memories used in mobile phones
· RAM (Random Access Memory) 
The RAM is used in mobile phones to store user data in mobile phones. So these a days we can store pictures, messages, ringtones, applications, themes and other these type of things in mobile phones so CPU stores these types of data in the RAM of our mobile phones.

· Flash (eeprom, ROM etc) 
The flash chip is used in mobile phones to hold mobile phone's operating system in it. so if the flash chip is damaged in mobile phones the phone cannot power on properly because all the instructions to start a mobile phones and its various tasks like call making , display etc are stored in the flash chip of mobile phones.

· Combo Chip 
In smoe mobile phones there is a combined type of memory used which is called combo memory chips these types of memories work for both like RAM and Flash.The clear example of this type of memory is used in Nokia 1100. Note: Multy Media Cards are not a part of mobile phones becaues they are used externally.