HOW THEY WORK

• A cell phone is basically like a • A cell phone uses one frequency to talk and another to

listen• When you make call, • When you talk the cell phone would send analog signals

to the tower, or with digital it would send waves.• Then the tower would send a signal to the other cell

phone that they have a call

HOW THEY WORK

• Then the towers will then open up a channel connect both cell phones

• When you driving your cell phone automatically switches over to another cell tower so you don’t loose your signal

• The signal that the cell phones and towers have are called frequencies.

• The phone and the tower send frequency signals each other when you are calling someone, basically every time you talk and listen

Samartphones

• Smartphone took the cell phone other level• You could now do multiple things at the same time• You could browse the internet• Check your email• Play games• Social Networking

1G vs. 2G

• 1G• In each cell has 56 voice channels, so only 56 people can be

talking at the same time• 2G• This was the step form analog to digital• Now the number of channels increases for 56 to 168

3G vs. 4G

• 3G• It was faster to transmit data than 2G• Also you could stream videos, audio, and much more.

• 4G• Its basically a step from 3G, faster.

Future of the phone

• IPhone 6• 3D• 5.5 inch screen• Face recognition Security• 10 MEGAPIXEL Camera rear and 8 in front• Full 1080p HD Recording AND 3D Video Recording /

Display• Samsung• Flexible phone

Sources

• http://electronics.howstuffworks.com/cell-phone2.htm

Global Positioning System

How They Work

GPS BACKGROUND

• The GPS was built by the US military in 1995.• There are currently 31 satellites angled at 55 degrees to

the equator.• The satellites orbit 20,000km (12,430miles) from the

earth and make two orbits per day.• The orbits are designed to have six satellites in view from

most places on earth.

HOW IT WORKS

• A GPS receiver gets a signal from a GPS satellite• The satellite transfers the exact time the signals are sent• By subtracting the time the signal was transferred from

the time it was received, the GPS determines how far it is from the satellite.

HOW IT WORKS (CONTINUED)

• A complication with the GPS is calculating the time it took for the signal to be received.

• GPS satellites have atomic clocks keeping precise time, but it isn’t feasible to give a receiver an atomic clock.

• If it receives a fourth satellite, it solves the equation it determines the exact time.

TRILATERATION

• A simple mathematical principal similar to triangulation and using a series of circles for two-dimensional problem solving, and spheres for three-dimensional problem solving.

WORKCITED

• http://www.maptoaster.com/maptoaster-topo-nz/articles/how-gps-works/how-gps-works.html