Communications in FE Electrical

Communication systems play a crucial role in our modern world, enabling the exchange of information over various mediums. From weather forecasting to aviation, military, global networking, you name it, communications is the crucial topic in the FE Electrical exam as per the NCEES® FE exam guidelines.

This blog post will cover Communications for the Electrical FE Exam preparation. Let’s start with the basics of Communications.

Types of Communication Systems

Before moving towards more technical details, it is necessary to cover various types of communications in FE Electrical. This includes wired and wireless communication systems, each with different categories. 

Wired Communication Systems

  • Optical Communication System – Optical communication Communications In FE Electrical uses light signals (typically laser or LEDs) to transmit data through optical fibers. It’s known for high bandwidth and low attenuation. Technical use cases include long-distance data transmission, such as in internet backbone networks. Example: Fiber-optic internet connections.
  • Coaxial Cable Communication System – Coaxial cables transmit electrical signals using a central conductor surrounded by insulating layers. These are suitable for high-frequency applications like cable TV and broadband internet.
  • Twisted Pair Communication System – Twisted pair cables have pairs of insulated copper wires twisted together. They are widely used in Ethernet networks, telephone lines, and local area networks (LANs).

Wireless Communication Systems

Radio Communication System – Radio waves are used to transmit data through the air. This includes everything from AM/FM radio broadcasting to cellular networks. Technical use cases include mobile communications. Example: 4G/5G cellular networks.

Microwave Communication System – Microwaves offer high-frequency wireless communication suitable for point-to-point connections. They are used for long-distance telephone and data transmission, as well as satellite communication.

Infrared Communication System – Infrared (IR) signals use light in the infrared spectrum for short-range data transfer. Common in remote controls, wireless headphones, and some data transfer protocols like IrDA.

Duplex Communication Systems

duplex communication systems
  • Simplex Communication – In simplex communication, data flows in one direction only. It’s used in situations where information is sent but not received in response. Example: Radio broadcasting.
  • Half Duplex Communication – Half duplex allows data to flow in both directions but not simultaneously. Think of a walkie-talkie where you press to talk and release to listen.
  • Full Duplex Communication – Full duplex permits simultaneous two-way communication. It’s commonly used in telephone conversations, video conferencing, and most wired and wireless data connections.

Tactical Communication Systems

  • Military Tactical Communication – These systems are designed for secure, reliable communication in military operations. They include encrypted radios, satellite links, and data networks. Example: SINCGARS (Single Channel Ground and Airborne Radio System).
  • Emergency Services Communication – First responders, such as police, fire, and medical teams, rely on tactical communication for coordination during emergencies. Example: P25 (Project 25) radio systems.

Satellite Communication Systems

  • Geostationary Satellite Communication – Geostationary satellites orbit the Earth at the same speed as its rotation, allowing for constant coverage. They are used for TV broadcasting and global internet services.
  • Low Earth Orbit (LEO) Satellite Communication – LEO satellites orbit closer to the Earth, offering lower latency and faster data transmission. Companies like SpaceX’s Starlink use LEO satellites for global internet access.

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Case Study – Air Defense Communication

Air Defense Systems are responsible for detecting, tracking, and intercepting aerial threats such as enemy aircraft and missiles. Effective communication is essential for coordinating these actions. Here are the different types of communications In FE Electrical that we study to implement in such a scenario:

Radar Communication

Radar systems play a pivotal role in air defense. They detect and track incoming threats and provide valuable data to air defense command centers.

Use Case: Radar systems continuously transmit electromagnetic signals and receive echoes from aircraft or missiles. This data is communicated to command centers to assess the threat’s trajectory and characteristics.

Data Link Communication

Data link communication systems enable the exchange of data, including radar tracks and target information, between radar sites, command centers, and interceptor aircraft.

Use Case: Data link networks facilitate real-time sharing of target data. For instance, a radar site detecting an incoming missile can quickly relay this information to a command center, allowing for rapid decision-making and interceptor deployment.

Voice Communication (Radio)

Voice communication, typically carried out through secure radio channels, allows for direct communication between air defense personnel, including radar operators, fighter pilots, and command center staff.

Use Case: Fighter pilots receive instructions and updates via radio from air defense controllers. Radar operators can also communicate with their counterparts and superiors to coordinate tracking and interception efforts.

Satellite Communication

Satellite communication systems provide secure, long-range, and redundant communication channels, particularly in remote or geographically dispersed air defense operations.

Use Case: In cases where traditional ground-based communication infrastructure may be compromised, satellite links ensure continuous communication between air defense command centers, even across vast distances.

Electronic Warfare (EW) Communication

EW systems are used to disrupt or deceive enemy communication and radar systems while safeguarding friendly communication.

Use Case: Air defense systems may employ EW techniques to jam or spoof enemy radar and communication systems, making it harder for adversaries to track or communicate with their own assets.

C4ISR Systems (Command, Control, Communications, Computers, Intelligence, Surveillance, and Reconnaissance)

C4ISR systems integrate various communication and data-sharing components into a unified network. They enable real-time situational awareness and command and control of air defense assets.

Use Case: C4ISR systems allow air defense commanders to monitor the airspace, make rapid decisions, and direct interceptor aircraft to engage threats effectively.

Secure Communication

ecurity is paramount in air defense communication to prevent unauthorized access and eavesdropping by adversaries.

Use Case: Encrypted communication protocols and secure networks ensure that sensitive information related to air defense operations remains confidential and protected from interception.

Signal Processing in Communication Systems

Signal processing is the backbone of modern communication systems, enabling the transmission of information accurately and efficiently. Several fundamental techniques play a vital role in communication, such as:


Filtering involves the selective removal or modification of specific frequencies in a signal. In communication, filters are used to eliminate unwanted noise and interference. They ensure that the signal being transmitted or received is as clean and clear as possible.

Filters come in various types, such as low-pass, high-pass, band-pass, and band-stop filters, each serving a specific purpose.


Modulation is the process of encoding information onto a carrier signal. It alters one or more of the carrier signal’s properties, such as amplitude, frequency, or phase, to carry the information. In amplitude modulation (AM), variations in the carrier signal’s amplitude represent the information. In frequency modulation (FM), the carrier signal’s frequency changes with the information.


Coding involves representing information in a format suitable for transmission and storage. This process often includes adding redundancy to the data to enhance error detection and correction. Error-correcting codes, like Reed-Solomon codes and convolutional codes, are commonly used in digital communication systems.

Encryption and Decryption

Encryption is the process of converting information into a secure, unintelligible format to protect it from unauthorized access during transmission or storage. Decryption reverses the encryption process to recover the original data.

Difference Between AM and FM

modulation fm vs am

AM (Amplitude Modulation)

  • In AM, the information is encoded by varying the amplitude (strength) of the carrier signal.
  • The carrier signal’s frequency remains constant, while the amplitude varies according to the information being transmitted.
  • AM signals are more susceptible to atmospheric noise, electrical interference, and fading. As a result, AM broadcasts may suffer from static, particularly during adverse weather conditions.
  • AM is commonly used in aviation communication systems, where long-distance transmission is essential. Aircraft communication radios often utilize AM for air traffic control and navigation purposes.

FM (Frequency Modulation)

  • In FM, the information is encoded by varying the frequency of the carrier signal.
  • Unlike AM, where amplitude changes, FM keeps the amplitude constant and varies the frequency. This makes FM signals less susceptible to amplitude-based noise and interference.
  • FM provides higher audio fidelity, making it suitable for music and voice broadcasts. It delivers clearer sound quality with minimal static or noise.
  • FM is widely used in broadcast radio, where audio quality is critical. It offers superior clarity and is favored for music and high-quality voice transmissions.

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Fun Fact about Pilot Experiences with AM Signals

In some cases, airplane pilots flying near international borders have reported picking up AM radio signals from neighboring countries. This phenomenon occurs due to the unique propagation characteristics of AM signals, especially at night when atmospheric conditions can enhance their range.

The curvature of the Earth and the reflection of AM signals off the ionosphere can allow these signals to travel greater distances than expected. Pilots tuning their radios have occasionally enjoyed unexpected entertainment by listening to radio stations from other countries while flying near borders.

This demonstrates the fascinating ability of AM signals to travel over long distances under certain conditions.

Transmission Media

Choosing the right transmission medium is critical for specific applications because each medium has its strengths and weaknesses. Making the appropriate selection ensures that a communication system meets its objectives effectively.

Transmission MediaUse-CasesWhere Not to UseAdvantagesDisadvantages
Optical Fibers– Long-distance data transmission (e.g., internet backbone)– Short-distance, low data rate applications– High bandwidth– Installation cost
– High-speed internet access (fiber to the home)– Sensitive to bending– Low signal loss (attenuation)– Vulnerable to physical damage
– Telecommunications networks– Harsh environments– Immune to electromagnetic interference (EMI)– Requires specialized equipment
Coaxial Cables– Cable television and broadband internet distribution– Long-distance transmission– Decent bandwidth– Limited bandwidth for long distances
– Networking within buildings and campuses– High-speed internet access– Resistance to EMI– Signal loss with distance
– CCTV (Closed-Circuit Television) systems– Sensitive to bending– Durable and long-lasting– Not ideal for very high frequencies
– In-building telephone and data connections– Harsh environments– Can carry both analog and digital signals– Installation complexity
Wireless Channels– Mobile communications (cellular networks)– Limited coverage areas– Mobility and flexibility– Susceptible to interference
– Wi-Fi networks (local area wireless)– Limited bandwidth– No physical infrastructure required– Limited security
– Satellite communication– High data rates– Accessibility in remote areas– Limited capacity
– Bluetooth, NFC (Near Field Communication)– High reliability– Quick deployment– Limited range

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Digital Communication Systems

Digital communication In FE electrical exam is the process of transmitting and receiving data in a digital format, where information is represented using discrete symbols or bits. Unlike analog communication, which uses continuous signals, digital communication uses discrete, quantized values.

Evolution of Digital Communication

evolution of digital communication

Digital communication has evolved over centuries, and its continued advancements have transformed the way we connect, share information, and conduct business in today’s digital age. Here’s a brief timeline of key milestones in its development:

  • Telegraph (1830s-1840s): The telegraph was an early form of digital communication, using Morse code to encode and transmit messages over long distances via electrical signals.
  • Telephone (1876): Alexander Graham Bell’s invention of the telephone introduced voice communication with analog signals. However, digital technologies later improved voice quality and introduced features like pulse-code modulation (PCM).
  • Fax Machine (Late 19th century): The fax machine allowed for the transmission of images and documents in a digital format over telephone lines.
  • Teletype (1920s): Teletype machines enabled the transmission of text messages over telegraph lines using a digital code.
  • Digital Signal Processing (DSP) (1960s): The development of DSP techniques improved signal processing, enabling more efficient encoding, modulation, and error correction in digital communication systems.
  • Digital Data Networks (1970s): The advent of digital data networks, such as ARPANET (precursor to the internet), marked a significant shift in communication. Packet-switched digital data transmission became the foundation of modern data networks.
  • Digital Cellular Networks (1980s): The introduction of digital cellular networks like GSM (Global System for Mobile Communications) and CDMA (Code Division Multiple Access) revolutionized mobile communication.
  • Internet and World Wide Web (1990s): The internet and the World Wide Web enabled global digital communication, making information and data accessible to millions of people worldwide.
  • Digital Television (2000s): The transition from analog to digital television (DTV) improved picture and sound quality, paving the way for high-definition (HD) and ultra-high-definition (UHD) television.
  • 5G Networks (2010s): The rollout of 5G networks brought even higher data rates, reduced latency, and enhanced connectivity, enabling advanced applications like the Internet of Things (IoT).

Key Components of Digital Communication Systems

Digital communication systems consist of several essential components that ensure the accurate and reliable transmission of digital data:

  • Encoding and Modulation – Encoding techniques convert digital information into a suitable format for transmission. Modulation processes vary the properties of carrier signals (e.g., amplitude, frequency, or phase) to represent digital symbols. Popular modulation schemes include Amplitude Shift Keying (ASK), Frequency Shift Keying (FSK), and Phase Shift Keying (PSK).
  • Error Correction – Error correction codes, such as Reed-Solomon codes and convolutional codes, add redundancy to the transmitted data, allowing receivers to detect and correct errors that may occur during transmission. This ensures data integrity.
  • Demodulation and Decoding – Demodulation is the process of extracting digital symbols from modulated carrier signals. Decoding reverses the encoding process, converting received data back into its original digital format.
  • Multiplexing and Demultiplexing – Multiplexing and digital communications techniques combine multiple data streams onto a single channel for efficient transmission. Demultiplexing separates these streams at the receiving end. Time-division multiplexing (TDM) and frequency-division multiplexing (FDM) are common multiplexing and digital communications methods.
  • Protocols and Network Layers – Communication protocols, organized into network layers (e.g., OSI model), govern how data is structured, routed, and transmitted in digital networks. These protocols ensure compatibility and standardized communication across diverse systems.
  • Modems (Modulator-Demodulator) – Modems convert digital data into analog signals for transmission over analog lines and vice versa. They play a crucial role in connecting digital devices to analog communication channels.
  • Digital Communication Media – Digital data can be transmitted over various media, including wired (e.g., optical fibers, coaxial cables, and twisted-pair cables) and wireless (e.g., radio waves, microwave, and satellite) channels.

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Communication Protocols and Standards

Communication protocols and standards are essential in ensuring seamless and interoperable data exchange between devices and systems. Let’s discuss some industry standards used globally, impacting the way people connect and communicate with each other over varying distances.


Ethernet has evolved over the years and remains a fundamental technology for wired LANs, data centers, and internet connectivity. Gigabit Ethernet and 10 Gigabit Ethernet are common in business and home networks, while data centers use 100 Gigabit and higher speeds.

Wi-Fi (Wireless Fidelity)

The need for wireless connectivity within homes, businesses, and public spaces led to the development of Wi-Fi. It addressed the demand for untethered access to the internet and local networks.

Wi-Fi is ubiquitous and widely used for wireless internet access in homes, offices, coffee shops, airports, and more. It also plays a crucial role in IoT (Internet of Things) by connecting smart devices, such as thermostats, security cameras, and smartphones, to local networks.


Bluetooth was created to address the need for short-range wireless communication between devices, such as mobile phones, headsets, and computer peripherals. It eliminated the hassle of cables and connectors. Bluetooth LE (Low Energy) is particularly popular in IoT applications, as it enables energy-efficient communication between devices.

TCP/IP (Transmission Control Protocol/Internet Protocol)

TCP/IP was created to enable data packets to travel across different networks and systems. It became the foundational protocol suite of the internet, ensuring global connectivity and communication. TCP/IP continues to be the backbone of the internet, enabling data transmission, routing, and addressing.

USB (Universal Serial Bus)

The need for a universal and standardized connection interface for peripherals, storage devices, and accessories led to the development of USB. It simplified the connectivity of various devices to computers and reduced compatibility issues.

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I hope you found all these topics helpful in preparing for the Communications for the Electrical FE Exam. According to NCEES ® exam guidelines and roadmaps, Communications In FE Electrical is the most important exam topic helping you in FE Electrical exam preparation. Explore Study for FE to check out our FE electrical preparation sources including practice problems, and read our detailed blog on formula sheet for FE Electrical exam. Our all-things FE electrical preparation sources help you ace the exam in your first attempt.


Licensed Professional Engineer in Texas (PE), Florida (PE) and Ontario (P. Eng) with consulting experience in design, commissioning and plant engineering for clients in Energy, Mining and Infrastructure.