JSwick

a Jennifer Swick

2. What is different about walkie talkies and cell phones?
==CB radios are **half-duplex** devices so two people talkingon a CB radio use the same frequency, so only one person can talk at a time. A cell phone is a **full-duplex** device. so you use one frequency for talking and a different frequency for listening.==

because the are made up of multiple cells
==4. How do the phones use the "cells" to send and receive messages? FSK uses **two frequencies**, one for 1s and the other for 0s, **switching** between the two to send information between the cell tower and the phone. Clever modulation and encoding schemes are required to convert the analog information to digital, compress it and convert it back again while maintaining an acceptable level of voice quality==