How Wireless Adaptors Work
Wi-Fi systems have become a popular choice for home networks. They enable computer users to access the Internet from different locations without having to run cables all over the house. The minimum requirements for a wireless network is that the home has a wireless router and a computer with a wireless network adapter. The router and the network adapter each contains a tiny transmitter and receiver to generate and pick up radio waves.
Other People Are Reading
-
Radio Waves
-
Everyone is familiar with radio. A transmitter at the radio station pulses out a signal that can be picked up by radios within the transmitter's signalling footprint. A transmitter for a radio station has to be powerful, and is expensive. Home systems use a radio wave frequency that is relatively cheap to generate but does not travel very far.
Frequencies
-
Radio signal are expressed as a frequency. The frequency is the rate at which the transmitter generates waves. Frequency also expresses the width of a wave, as more waves occupying the same time frame have to be thinner. Radio frequencies are measured in Hertz; a thousand Hertz is a KiloHertz; a million Hertz is a MegaHertz; a thousand million Hertz is a GigaHertz. Wi-Fi systems operate within a frequency range that is classified as "microwave." The microwave definition applies to frequencies between 1 GHz and 100 GHz. Wi-Fi networks use either 2.4 GHz or 5 GHz. A "dual-band" system uses both.
-
Responsibilities
-
The wireless adapter receives data from the computer and has to convert that into a format that can be transmitted. Data moves around computers on parallel wires. That is, the eight bits of a byte travel side by side on eight separate wires. The first thing the adapter does is alter this data into serial data. Serial data puts those eight bits into a queue so they travel one after the other. Next, the adapter has to listen for momentary silence on the frequency so that the waves it sends out don't get mixed with other signals. A conductor on the network adapter then generates a magnetic wave to send the data out.
Carrier Waves
-
Although digital data can easily be converted into wave form, the process of transmitting data is not that simple. Computers deal with binary, which only has two numbers: zero and one. Zero and one are easy for electrical machines to represent because they are two states: on/off or high/low. On wired networks, these numbers are represented by a high voltage and a low voltage. In wireless systems, they are represented by a square wave. The wave cannot just be sent out by itself. The conductor generates a regular wave, pulsing at 2.4 or 5 GigaHertz. These are called "carrier waves." The square wave containing the data is then merged with the waves, altering their shape. This process is called modulation. When the receiver in the wireless router picks up these waves, it has to subtract the known shape of the carrier wave, which is called demodulation. This results in the data wave, which it pumps into a chip as a series of zeros and ones that can be interpreted as data.
-
References
- Photo Credit Creatas Images/Creatas/Getty Images
