INSIDE A CELL-PHONE

A basic digital cell phone contains just a few individual parts:

• A circuit board containing the brains of the phone
• An antenna
• An Liquid Crystal Display (LCD) screen
• A keyboard
• A microphone
• A speaker
• A battery
The circuit board is the heart of the system and contains several chips. The analog-to-digital and
digital-to-analog conversion chips translate the outgoing audio signal from analog to digital and


the incoming signal from digital back to analog. The digital signal processor (DSP) is a highly
customized processor designed to perform signal-manipulation calculations at high speed. The
microprocessor handles all the functions for the keyboard and display, deals with command and
control signaling with the base station and also coordinates the rest of the functions on the
board.The Read Only Memory (ROM) and Flash Memory chips provide storage for the phone's
operating system and customizable features, such as the phone directory. The Radio Frequency
(RF) and power section handles power management and recharging, and also deals with the
hundreds of FM channels. Finally, the RF amplifiers handle signals traveling to and from the
antenna.
The display has grown considerably in size as the number of features in cell phones have
increased. Most current phones offer built-in phone directories, calculators and games. And
many of the phones incorporate some type of PDA or Web browser. Some phones store certain
information, such as the SID and MIN codes, in internal Flash memory, while others use external
cards. Cell phones have tiny speakers and microphones.