Wireless Network Is the the technology of data transmission from one point to point without physical cable, including radio, cellular, infrared, and satellite.Radio is the transmission and reception of signals with wave electromagnetic wirelessly. Electromagnetic Waves presenting all frequencies. Spectrum Radio Frequency (RF) occupies a range of 9 KHz - 300 GHz.
Wave Anatomy :
And The frequency calculate with:
A radio signal sent to a another point, the signals must be modulated into a frequency signal (carrier), which is a constant and higher frequency of the input signal frequency. Reason modulation is required:
1. For a better transmission, because the radio signals that we send mostly using low frequency
2. To allow multiple signals simultaneously transmitted without disturbing each other (interference). Read the back Frekuency Division Multiplexing (FDM)!
Analog Modulation:
Digital Modulation:
FSK is used in the 802.11 specification for modulation Frequency Hopping Spread Spectrum (FHSS) and Direct Sequence Spread Spectrum (DSSS).
No comments:
Post a Comment