What is Analog FDMA Cell Phone Technology?
Advantages of Digital Networks Over Analog Networks
There are three main cellular technologies: Older Analog/FDMA, Modern TDMA, Newer CDMA
Analog transmission is considered an "older" cellular phone technology.
Analog technology was built in the early 1980's. Analog allows a cellular phone to transmit signals by sending voice, video, and data that are always changing, and so does the network systems. Analog is considered an older method of modulating voice or data information radio signals.
Analog transmissions uses FDMA technology. FDMA stands for "frequency division multiple access". FDMA is used exclusively for analog cellular systems, even though in theory FDMA can also be used with digital. Essentially, FDMA splits the allocated spectrum into many channels. In current analog cell systems, each channel is 30 kHz. When a FDMA cell phone establishes a call, it reserves the frequency channel for the entire duration of the call. The voice data is modulated into this channel’s frequency band (using frequency modulation) and sent over the airwaves. At the receiver, the information is recovered using a band-pass filter. The phone then uses a common digital control channel to acquire channels.
FDMA analog transmissions are the least efficient cellular networks since each analog channel can only be used one user at a time. Analog channels don't take full advantage of band-width. Not only are these FDMA channels larger than necessary given modern digital voice compression, but they are also wasted whenever there is silence during a cell phone conversation. Analog signals are especially susceptible to noise and the extra noise cannot get filtered out. Given the nature of the signal, analog cell phones must use higher power (between 1 and 3 watts) to get acceptable call quality. Given these analog features, it is easy to see why FDMA is being replaced by newer digital networks such as TDMA and CDMA.
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