RF Theory Flashcards
Gain
Is the amplification of a signal which can compensate for losses. It is possible to adjust the gain settings in both the transmitter and receiver to produce the correct output signal strength
What are the three components of Radio Frequency Waves?
Amplitude, Frequency, Phase
Phase
Where the phase is at any given moment.
Wavelength
The distance between a given point on one cycle and the same point on the next cycle.
Impedance
Describes the resistance a circuit presents to alternating current and is measured in ohms.
Refraction
Is the changing or bending of waves where the boundary of one medium meets another.
Attenuation
Is defined in physics as the decrease in a property, as energy, per unit of a wave of a beam of particles, which increases as a result of absorption, scattering, spreading in three dimensions, etc.
FM Frequency modulation
If this input signal is added to the pure carrier wave, it will thereby change the frequency of the carrier wave. In that way, users can use changes of frequency to carry speech information.
Velocity
Signals speed in a particular direction.
Inter-Modulation Interference
Is produced by mixing together several different signals, generally from different radio systems.
What are the four main types of Interference?
Co-Channel Interference, Adjacent Channel Interference, Inter-modulation interference, Unintended Electromagnetic Radiation
Unintended Electromagnetic Radiation
This is produced from non-radio systems like power lines, transformers, solar flares, etc.
Carrier Wave
Is a high frequency signal which has a specific amplitude, frequency, and phase levels, but it does not hold any data.
Reflection
Occurs when a wave encounters an obstruction and is not absorbed
Frequency (RF)
The number of waves passing through in a given second
Amplitude
The height of the wave (or power given to make the signal)
What are the three components of Radio Frequency Waves?
Amplitude, Frequency, Phase
AM Amplification modulation
The fluctuations in power (amplitude) of the wave carries the data.
Modulating Signal
This signal is what holds the message or traffic. Signals are sent through what is called a modulator to attach onto a signal and is then sent out across the airwaves to a destination.
Active Gain
Uses an RF amplifier to increase the signal strength. The amplifier is placed in path between the AP and antenna or between the radio and antenna.
Diffraction
Is when radio signals encounter an obstacle they tend to travel around the obstacle. This means that even if the direct path of a signal is blocked, the “new” wave will continue to spread out in 3 dimensions, even though there is not Line-Of-Sight (LOS).
Voltage Standing Wave Ratio (VSWR)
describes the ratio of mismatch. If this is high enough, the standing wave can cause signal distortion and damage the transmitter.
Passive Gain
Uses no extra amplification and relies fully on the directionality of the antenna for increased RF energy in a desired direction.
What are the 3 components to Electromagnetic Waves?
Frequency, Wavelength, Velocity
Adjacent Channel Frequency
Occurs when channels are on a different set of frequencies but are too close together
Absorption
Occurs when a radio wave hits an object, and some of its energy is absorbed rather than redirected.
Multi-Path
Occurs when a coherent signal takes multiple paths to a destination, and arrives out of phase.
Multi-path fading is generally destructive to an RF signal
Attenuation is generally caused by what three things?
Frequency/Noise, Physical Surroundings, Distance
Co-Channel Interference
Signals are on the same Frequency
Frequency (EM)
The number of times that a particular point on the wave moves up and down in a given time (normally measured in seconds).
Modulation
Is process by which voice, music, and other “intelligence” is added to the radio waves produced by a transmitter.
Is the amplification of a signal which can compensate for losses. It is possible to adjust the gain settings in both the transmitter and receiver to produce the correct output signal strength
Gain
Amplitude, Frequency, Phase
What are the three components of Radio Frequency Waves?
Where the phase is at any given moment.
Phase
The distance between a given point on one cycle and the same point on the next cycle.
Wavelength
Describes the resistance a circuit presents to alternating current and is measured in ohms.
Impedance
Is the changing or bending of waves where the boundary of one medium meets another.
Refraction
Is defined in physics as the decrease in a property, as energy, per unit of a wave of a beam of particles, which increases as a result of absorption, scattering, spreading in three dimensions, etc.
Attenuation
If this input signal is added to the pure carrier wave, it will thereby change the frequency of the carrier wave. In that way, users can use changes of frequency to carry speech information.
FM Frequency modulation
Signals speed in a particular direction.
Velocity
Is produced by mixing together several different signals, generally from different radio systems.
Inter-Modulation Interference
Co-Channel Interference, Adjacent Channel Interference, Inter-modulation interference, Unintended Electromagnetic Radiation
What are the four main types of Interference?
This is produced from non-radio systems like power lines, transformers, solar flares, etc.
Unintended Electromagnetic Radiation
Is a high frequency signal which has a specific amplitude, frequency, and phase levels, but it does not hold any data.
Carrier Wave
Occurs when a wave encounters an obstruction and is not absorbed
Reflection
The number of waves passing through in a given second
Frequency (RF)
The height of the wave (or power given to make the signal)
Amplitude
Amplitude, Frequency, Phase
What are the three components of Radio Frequency Waves?
The fluctuations in power (amplitude) of the wave carries the data.
AM Amplification modulation
This signal is what holds the message or traffic. Signals are sent through what is called a modulator to attach onto a signal and is then sent out across the airwaves to a destination.
Modulating Signal
Uses an RF amplifier to increase the signal strength. The amplifier is placed in path between the AP and antenna or between the radio and antenna.
Active Gain
Is when radio signals encounter an obstacle they tend to travel around the obstacle. This means that even if the direct path of a signal is blocked, the “new” wave will continue to spread out in 3 dimensions, even though there is not Line-Of-Sight (LOS).
Diffraction
describes the ratio of mismatch. If this is high enough, the standing wave can cause signal distortion and damage the transmitter.
Voltage Standing Wave Ratio (VSWR)
Uses no extra amplification and relies fully on the directionality of the antenna for increased RF energy in a desired direction.
Passive Gain
Frequency, Wavelength, Velocity
What are the 3 components to Electromagnetic Waves?
Occurs when channels are on a different set of frequencies but are too close together
Adjacent Channel Frequency
Occurs when a radio wave hits an object, and some of its energy is absorbed rather than redirected.
Absorption
Occurs when a coherent signal takes multiple paths to a destination, and arrives out of phase.
Multi-path fading is generally destructive to an RF signal
Multi-Path
Frequency/Noise, Physical Surroundings, Distance
Attenuation is generally caused by what three things?
Signals are on the same Frequency
Co-Channel Interference
The number of times that a particular point on the wave moves up and down in a given time (normally measured in seconds).
Frequency (EM)
Is process by which voice, music, and other “intelligence” is added to the radio waves produced by a transmitter.
Modulation
