Cell Phones are a very helpful way of communicating. Did you know that a cell-phone is actually a complicated radio? Some interesting facts about a cell phone is that areas are divided into small cells, with a cell phone tower at the center of each cell. The difference beween a walkie talkie and a cell phone is that walkie talkies can communicate as far as 1000 ft. and cell phones can transmit several miles away from the cell tower. Another difference is that on a walkie talkie only one person can talk at a time. With a cell phone, two people can talk at a time.

Cell phones have low power transmitters. The two signal strenghts that a cell phone has are 0.6 watts and 3 watts. Advanced Mobile Phone systems are the first common cell phone systems in the United States. It uses a range of frequencies between 824 MHz and 894 MHz for analog cell phones. Digital cell phones convert voice into binary information, 1's and 0's, and then compress it. This compression allows between 3 and 10 digital cell phone calls to occupy the space of a single analog cell phone call. Cell phone networks use three common thechnologies for transmitting information. They are the Frequency-Division Multiple Access, Time-Division Multiple Access, and Code-Division Multiple Access.

If you ever take apart a cell phone, you will find an amazing circut board that contains the brains of the phone, an antenna, a liquid crystal display, a keyboard, a microphone, a speaker, and a battery. There are also many computer chips inside a cell phone. The analog-to-digital and digital-to-analog conversion chips translate the outgoing audio signal. There is a digital singnal processor, and a microproccesor. This is what the cell phone is all about.