Chapter 3Radio Frequency
Components, Measurements, and Mathematics
Key Terms & Concepts
3 Basic Requirements for Communication Two or more devices want to
communicate Medium or method for them to
communicate Set of rules for them to use
Key Terms & Concepts Transmitter
Generates signal at specific frequency Determines amplitude (power level)
of signal Antenna
Collects AC signal that receives from transmitter
Directs, or radiates, RF waves away from the antenna in a specific pattern
Key Terms & Concepts
Receiver Receives the signal from the antenna
and translates the signal into 1s and 0s Intentional Radiator (IR)
Specifically designed to generate RF Consists of all components from
transmitter to antenna, excluding antenna
Key Terms & Concepts
Equivalent Isotropically Radiated Power (EIRP) Highest RF signal strength
transmitted from antenna Focuses the RF generated by the IR and
makes it stronger
Key Terms & Concepts Units of Power
Watt 1 Watt = 1 ampere (amp) of current flowing at 1
volt Amp is current Voltage is pressure generated Amount of watts generated = volts X amps
Milliwatt (mW) 1/1,000 of a watt
Decibels relative to 1 milliwatt (dBm) Compares signal to 1 milliwatt of power 0 dBm = 1 milliwatt
Key Terms & Concepts Units of Comparison
Decibel (dB) Represents difference
btw 2 values Decibels isotropic
(dBi) Gain or increase of
power from an antenna when compared to what an isotropic radiator would generate
Milliwatts Decibel change
.01 -20
.1 -10
1 0
10 +10
100 +20
1000 +30
10000 +40
Key Terms & Concepts
Units of Comparison Decibels dipole (dBd)
Increase in gain of an antenna when it is compared to the signal of a dipole antenna
If antenna has value of 3 dBd, it is 3 dB greater than a dipole antenna
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