Microwave Basics

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6g

după jdjdjdjj jfjjfjdj

Reaganland

după B Reagan

E.M. Spectrum

după Peter Clark

Variance and Standard Deviation

după FEDERICO ALEJANDRO RODAS SOTO

QAM

Subtopic

Bandwidth

Microwave Basics

Link fading (Dispersion)

Rain attenuation

Refers to scenarios where signal is absorbed by rain, snow, ice • Absorption becomes significant factor above 11GHz • Signal quality degrades • Represented by “dB/km” parameter which is related the rain density which represented “mm/hr” • Rain drops falls as flattened droplet  V better than H (more immune to rain fading)

Climatic

Terrain

Atmospheric (refraction)

Multipath/ducting

Multipath transmission is the main cause of fading in LOW frequencies

Multipath occurs when there is more then one beam reaching the receiver with different amplitude or phase

Humidity/Gas

Dispersion

Electromagnetic signal propagating in a physical medium is degraded because the various wave components (i.e., frequencies, wavelengths) have different propagation velocities within the physical medium: • Low frequencies have longer wavelength and refract less • High frequencies have shorter wavelength and refract more

Antennas

Modulation

Digital

QAM – Quadrature Amplitude modulation

PSK – Phase Shift Keying

FSK – Frequency Shift Keying

ASK – Amplitude Shift Keying

Analog

PM – Phase modulation

FM - Frequency modulation

AM - Amplitude modulation