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