Chapter 2 Flashcards
What is EM?
Electromagnetic Spectrum
Which is usually simply referred to as spectrum is the range of all possible electromagnetic radiation.
Low Frequency?
High Frequency?
Low Frequency - Long Wavelength
High Frequency - Short Wavelength
How much is 1 Ghz?
1,000,000,000 (billion) cycles per second
What is Absorption?
When signal gets absorbed by some material.
Leading cause of attenuation (loss)
What is Reflection?
When wave bounces off a material.
Sky Wave Reflection?
Can occur in frequencies below 1Ghz, where the signal has very large wavelength.
Microwave Reflection?
Exist between 1Ghz and 300Ghz. Much smaller frequencies
Scattering?
Scattering is multiple reflections.
Chain link fences, tree folliage, rocky terrain.
Refraction?
Bending of RF signal
FSPL?
Free Space Path Loss
Is the loss of signal strength caused by the natural broadening of the waves.
Multipath?
Is a propagation phenomenon that results in two or more paths of a signal arriving at the same time or within nanoseconds of each other.
Four possible results of Multipath?
Upfade
Downfade
Nulling
Data Corruption
What is Upfade?
Increased signal strength.
What is Downfade?
Decreased signal strength.
What is Nulling?
Signal cancellation
What is Data Corruption?
Corrupted Data
R: What are some results of multipath interference?
Upfade
Excessive Retransmissions
R: What term best defines the linear distance traveled in one positive-to-negative-to-positive oscillation of an electromagnetic signal?
Wavelength
Which of the following statements are true about amplification?
RF amplifiers require an outside power source
Antennas are passive gain amplifiers that focus the energy of a signal in one direction
Signal strength may passively increase because of multipath upfade
A standard measurement of frequency is called?
Hertz
When an RF signal bends around an object, this propagation behaviour is known as what?
Diffraction
What is the frequency of an RF signal that cycles 2.4 million times per second?
2.4Mhz
What can result in multipath?
Refraction
Diffraction
Reflection
Scattering
What term is used to describe the time differential between a primary signal and a reflected signal arriving at a receiver?
Delay Spread
