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5 sie 2020 · Cable television is a system of delivering television programming to consumers via radio frequency (RF) signals transmitted through coaxial cables, or in more recent systems, light pulses through fibre-optic cables.
Typically two frequencies are used to set up the communication channel. Each frequency is used solely for either transmitting or receiving. Applies to Frequency Division Duplex (FDD) systems. Example: Cellular phones, satellite communication.
Propagation models (PM) are being used to predict: average signal strength at a given distance from the transmitter. variability of the signal strength in close spatial proximity to a particular location. PM can be divided into: large-scale models (mean signal strength for large transmitter receiver separation)
27 lis 2015 · • Cable television is a system of delivering television programming to paying subscribers via radio frequency (RF) signals transmitted through coaxial cables or light pulses through fiber-optic cables. • Cable television, introduced in the 1970s, offers a greater number of channels, while solving antenna reception problems.
21 lis 2017 · RF signals are electromagnetic waves that propagate through the air and other materials, exhibiting behaviors like reflection, scattering, and multipath. Key characteristics of RF signals include wavelength, frequency, amplitude, and phase. Wavelength is inversely related to frequency, while amplitude determines signal strength.
1 wrz 2006 · 18 Voltage Standing Wave Ratio (VSWR) VSWR occurs when there is a mismatched impedance between devices in an RF signal. For example, if the cable leading to the antenna is 50 ohms and the connector to the antenna is 75 ohms then an impedance mismatch has occurred.
Definition of “ power waves”(1) The waves going towards the n-port are a = (a 1, a 2, ..., an), the waves travelling away from the n-port are b = (b 1, b 2, ..., bn). By definition currents going into the n-port are counted positively and currents flowing out of the n-port negatively. The wave a.
