Microwave network connection
Introduction
Microwave radio communication refers to the transmission of data or voice through radio frequencies with wavelengths in the microwave frequency region.[1].
Definition
Microwaves are electromagnetic waves with frequencies (f) between f=300 MHz and f=300 GHz, whose oscillation periods (T=1/f) are between 3.3 x10e-9 and 3.3 x10e-12 seconds, with wavelengths in the range of 1 meter in 300 MHz to 1 millimeter in 300 GHz. Other definitions, for example Those of the IEC 60050 and IEEE 100 standards place their frequency range between 1 GHz and 30 GHz, that is, wavelengths between 30 centimeters and 10 millimeters.
The microwave range is included in the radio frequency bands. From 0.3 to 3 GHz in the UHF (ultra high frequency or ultra high frequency), from 3 to 30 GHz in the SHF (super high frequency or super high frequency) and from 30 to 300 GHz in the EHF (extremely high frequency or extremely high frequency). Microwaves with higher frequencies and shorter wavelengths are called millimeter waves.
Much of the communication systems established since the mid-1980s are digital in nature and logically transport information in digital form. However, terrestrial microwave repeater radio systems using FM or digitally modulated carrier frequencies in either QAM or PSK continue to constitute 35% of the total information transport circuits in the United States. There are a variety of microwave systems operating at distances that vary from 15 to 4000 miles. Intrastate service or feeder microwave systems are generally considered short range, because they are used to carry information over relatively short distances, for example making radio communication between cities that are in the same country. Long-range microwave systems are those used to carry information over relatively much longer distances, for example, in interstate route and primary network applications. The capabilities of microwave radio systems range from less than 12 voice band channels to more than 22,000. Early systems had frequency division multiplexed voice band circuits, and used conventional, non-coherent frequency modulation techniques, more modern ones have pulse coding modulated and time division multiplexed voice band circuits and use more modern digital modulation techniques, such as switching modulation. phase (PSK) or quadrature amplitude (QAM).