Erstellt von Amit Pindoria
vor etwa 7 Jahre
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Frage | Antworten |
The distance between the two successive crescents (peaks) or two successive throughs (valleys) | A wavelength |
how often an RF signal cycles in a certain time period | Frequency |
Frequency of 1,000,000,000 (billion) cycles per second | 1Ghz |
The height of the wave | Amplitude |
Most common RF behaviour | Absorption |
Wave hits smooth object that is larger than the wave itself, dependant on the material the signal may bounce in another direction | Reflection |
Multiple reflections | Scattering |
Signal passes through a medium with different density causing the wave to change direction. | Refraction |
Causes of refraction | - Water Vapour - Changes in air temperature - Changes in air pressure |
Signal is bent around an object | Diffraction |
Decrease in amplitude | Loss (Attenuation) |
Loss of signal strength caused by the natural broadening of the waves | Free Space Path Loss (FSPL) |
Occurs when 2 or more signals arrive at the receiving station at the same time or within nanoseconds of each other | Multipath |
Multiple RF signal paths arrive at the same time and are in phase (phase differences of 0 to 120 degrees) will result in increased signal strength | Upfade |
Multiple RF signals arrive at the same time but are out of phase (phase difference of 121 to 179 degrees) Results in decrease signal strength | Downfade |
Multiple RF signals arrive at the same time and are 180 degrees out of phase of each other | Nulling |
Multiple signals arriving but not at the same time the receiver might have trouble demodulating the signal. | Data Corruption |
Increase to signal on the transmitter or transceivers side through the use of an amplifier. | Active Gain |
Focusing the antenna, the inner workings of the antenna make the signal stronger. | Passive Gain |
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