Radio Frequency Faundamentals Flashcards
Wavelength
A fundamental characteristic of RF which describes the distance between two successive crests (or troughs) of a wave pattern.
Frequency
A fundamental characteristic of RF which describes the number of cycles an RF experiences in a certain time interval.
Amplitude
A fundamental characteristic of RF which describes the strength or power of a signal.
Phase
A fundamental characteristic of RF which describes the relationship between two or more signals, specifically, the positioning of the position of the peaks and troughs of the signals.
Wave Propagation
A term which describes the way in which RF signals travel away from an antenna.
Absorption
A behavior of RF where when a signal encounters a material, it can be “absorbed” by that material, meaning that the signal strength is either partially or fully diminished without a byproduct.
Reflection
A behavior of RF where when a signal encounters an object larger than a wave itself, depending on the material and surface the wave may bounce in another direction.
Scattering
A behavior of RF where when a signal hits a surface capable of reflection, but is “scattered” in that many smaller, less powerful signals are reflected in multiple directions.
Refraction
A behavior of RF where when a signal encounters a material of a varied density, a change in direction of the signal, or a bend in the path of the signal.
Diffraction
A behavior of RF where when a signal encounters an object, it bends around the object, taking the path of least resistance.
Attenuation
A term used to describe a loss in amplitude (or strength) due to the behaviors of RF signals.
Free Space Path Loss
A behavior of RF where as a signal travels, the signal will attenuate despite the lack of obstructions. This is not a linear function.
Multipath
An phenomenon where two or more paths of a signal arrive at a receiving antenna at the same time.
Upfade
A constructive multipath phenomenon where multiple signals arrive at the receiver either in phase or partially out of phase (less than 120 degrees) causing an increase in signal strength.
Downfade
A destructive multipath phenomenon where multiple signals arrive at the same time but are out of phase with the primary wave (greater than 120 degrees) causing a reduction in the signal strength.
Nulling
A destructive multipath phenomenon where multiple signals arrive at the receiver completely out of phase (180 degrees) causing a complete cancellation of the signal.
Data Corruption
A destructive multipath phenomenon where multiple signals arrive at the receiver at slightly different times causing issues demodulating the signal into ones and zeros.
Gain
A term used to describe an increase in amplitude in an RF signal.
Passive Gain
A term used to describe the effect of focusing a RF signal in a single direction.
Active Gain
A term used to describe the effect of using an amplifier on the wire that connects the transceiver to the antenna.
How is Wavelength related to Frequency?
An inverse relationship, if Wavelength goes up, Frequency goes down.
