Fundamentals of Electronic Communications - Module 2 Flashcards

Vocabulary practice flashcards covering key terms, frequency allocations, wavelength definitions, and optical spectrum classifications from Module 2.

Electromagnetic Spectrum

The complete range of frequencies of electromagnetic radiation that propagate energy and travel through space in the form of waves.

Radio Spectrum

The portion of the electromagnetic spectrum made up of longer wavelengths with lower frequencies.

Optical Spectrum

The portion of the electromagnetic spectrum made up of shorter wavelengths with higher frequencies, consisting of infrared, visible, and ultraviolet light waves.

Visible Spectrum

The portion of the optical spectrum that humans can see, with light wavelengths ranging from $400$  to $800\,\text{nm}$.

Frequency ($f$)

The number of cycles of a repetitive wave that occurs in a given time period, measured in Hertz ($\text{Hz}$).

Wavelength ($\lambda$)

The distance occupied by one cycle of a wave, usually expressed in meters ($\text{m}$).

Speed of Light ($c$)

The speed of electromagnetic waves in free space, equal to $300{,}000{,}000\,\text{m/s}$ or $3 \times 10^8\,\text{m/s}$.

Bandwidth ($\text{BW}$)

The portion of the electromagnetic spectrum occupied by a signal, or the frequency range over which a communication circuit operates, calculated as $\text{BW} = f_2 - f_1$.

Extremely Low Frequencies (ELF)

Signals in the frequency range of $30\,\text{Hz}$ to $300\,\text{Hz}$, which include power line frequencies ($50\,\text{Hz}$ and $60\,\text{Hz}$) and the low end of human audio.

Ultra Low Frequencies (ULF)

Signals in the frequency range of $300\,\text{Hz}$ to $3\,\text{kHz}$, representing the normal range of human speech, also referred to as voice frequency.

Voice Frequency

The normal range of human speech, operating in the Ultra Low Frequency (ULF) band from $300\,\text{Hz}$ to $3000\,\text{Hz}$.

Very Low Frequencies (VLF)

Signals in the frequency range of $3\,\text{kHz}$ to $30\,\text{kHz}$, including the higher end of human hearing up to about $15\,\text{kHz}$ or $20\,\text{kHz}$, musical instruments, and military communication.

Low Frequencies (LF)

Signals in the frequency range of $30\,\text{kHz}$ to $300\,\text{kHz}$, primarily used for aeronautical and marine navigation, subcarriers, and also known as the kilometer band.

Kilometer Band

Another designation for the Low Frequencies (LF) band, covering frequencies from $30\,\text{kHz}$ to $300\,\text{kHz}$.

Medium Frequencies (MF)

Signals in the frequency range of $300\,\text{kHz}$ to $3000\,\text{kHz}$, also known as the hectometer band, primarily used for AM radio broadcasting ($535$ to $1605\,\text{kHz}$).

Hectometer Band

Another designation for the Medium Frequencies (MF) band, covering frequencies from $300\,\text{kHz}$ to $3000\,\text{kHz}$.

High Frequencies (HF)

Signals in the frequency range of $3\,\text{MHz}$ to $30\,\text{MHz}$, also known as short waves, used for simplex broadcasting, two-way radio, amateur radio, CB, and military communications.

Short Waves

Another designation for the High Frequencies (HF) band, covering frequencies from $3\,\text{MHz}$ to $30\,\text{MHz}$.

Very High Frequencies (VHF)

Signals in the frequency range of $30\,\text{MHz}$ to $300\,\text{MHz}$, widely employed for television, FM radio broadcasting ($88$ to $108\,\text{MHz}$), and mobile radio communications.

Ultra High Frequencies (UHF)

Signals in the frequency range of $300\,\text{MHz}$ to $3000\,\text{MHz}$, also known as the decimeter band, used for UHF TV, land mobile communications, cellular phones, radar, and navigation.

Decimeter Band

Another designation for the Ultra High Frequencies (UHF) band, covering frequencies from $300\,\text{MHz}$ to $3000\,\text{MHz}$.

Super High Frequencies (SHF)

Signals in the frequency range of $3\,\text{GHz}$ to $30\,\text{GHz}$, referred to as microwaves, widely used for satellite communication, radar, wireless LANs, and cellular systems.

Microwaves

Electromagnetic signals operating in the Super High Frequency (SHF) band from $3\,\text{GHz}$ to $30\,\text{GHz}$.

Extremely High Frequencies (EHF)

Signals in the frequency range of $30\,\text{GHz}$ to $300\,\text{GHz}$, referred to as millimeter waves, used for satellite telephony, computer data, short-haul cellular networks, and specialized radar.

Millimeter Waves

Electromagnetic signals with frequencies higher than $30\,\text{GHz}$ up to $300\,\text{GHz}$ in the Extremely High Frequency (EHF) band.

Infrared

Light waves with wavelengths ranging from $0.1\,\text{mm}$ to $0.7\,\mu\text{m}$, produced by heat-generating objects, light bulbs, LEDs, and lasers, and utilized in fiber optic communication.

Ultraviolet

Light waves with wavelengths ranging from $4\,\text{nm}$ to $400\,\text{nm}$, generated by mercury vapor lights and sun lamps, primarily used in medical applications.

Subcarriers

Signals modulated by baseband information that operate within the Low Frequency (LF) band range.