Analog Communications

Course Description

This course is an introduction to electronic communications with an emphasis on analog techniques. It covers the fundamental circuit building blocks of communication circuits such as oscillators, mixers, filters, tuned circuits, and phase-locked loops (PLLs). Topics include amplitude modulation, frequency modulation, multiplexing and demultiplexing, satellite communications, antennas, and other modern electronic communication technologies. The "C" lab indicator designates this as a combined lecture and laboratory course meeting in the same place at the same time, providing hands-on experience with test equipment and communication circuit construction and troubleshooting.

This course falls under the Florida SCNS taxonomy: Engineering Technologies > Electronic Engineering Technology (EET), course number 2323C, indicating a sophomore-level combined lecture/laboratory course. It is offered at multiple Florida State College System institutions, including Miami Dade College and Eastern Florida State College.

Learning Outcomes

Required Outcomes

Upon successful completion of this course, students will be able to:

Describe a basic communication system and explain the need for modulation in radio-frequency transmission.
Analyze and calculate power, voltage, current, and modulation index in both AM and FM systems.
Explain the operation of oscillator circuits (Colpitts, Hartley, Crystal) used to generate carrier frequencies.
Analyze the operation of mixers, tuned circuits, and RF/IF amplifier stages within a communications system.
Describe and analyze Amplitude Modulation (AM) transmitter and receiver circuits, including envelope detectors and AGC.
Describe and analyze Frequency Modulation (FM) transmitter and receiver circuits, including limiters and discriminators.
Explain the operation of a Phase-Locked Loop (PLL) and apply it to FM generation and detection.
Analyze the operation of a superheterodyne receiver and identify the function of each stage.
Define electrical noise, explain types of noise, and describe noise effects on communications receivers.
Perform laboratory measurements on AM/FM transmitter and receiver circuits using oscilloscopes, multimeters, and spectrum analyzers.
Troubleshoot communication circuits by identifying faults through systematic circuit modification and measurement.
Describe Frequency Division Multiplexing (FDM) and its role in multi-channel communications systems.

Optional Outcomes

The following outcomes may be included at the discretion of the instructor or institution:

Discuss Single Sideband (SSB) and Double Sideband Suppressed Carrier (DSB-SC) modulation techniques and compare them to standard AM.
Explain Vestigial Sideband (VSB) modulation and its application in analog television broadcast.
Analyze pre-emphasis and de-emphasis filtering techniques used in FM broadcast systems.
Describe basic satellite communications systems, including uplink/downlink concepts and transponder operation.
Explain antenna types, radiation patterns, gain, and the principles of electromagnetic wave propagation.
Describe transmission line characteristics including impedance matching and standing wave ratio (SWR).
Perform power level analysis (in dBm) at each stage of an AM/FM transmitter/receiver system.
Describe the principles of analog television and the transition to HDTV.

Major Topics

Required Topics

Introduction to Communication Systems
- Block diagram of a communication system (transmitter, channel, receiver)
- Need for modulation; frequency spectrum and bandwidth concepts
- Signal-to-Noise Ratio (SNR) fundamentals
- Decibel notation (dB, dBm) and power calculations
Communication Circuit Building Blocks
- LC tuned circuits and resonance
- RF filters (low-pass, high-pass, bandpass)
- Oscillators: Colpitts, Hartley, Crystal-controlled
- Mixers and frequency translation
- RF and IF amplifiers
Amplitude Modulation (AM)
- AM waveform, modulation index, and bandwidth
- AM power distribution (carrier and sidebands)
- AM modulator circuits (low-level and high-level)
- AM demodulation: envelope detector and product detector
- AM transmitter and receiver block diagrams
- Automatic Gain Control (AGC)
Frequency Modulation (FM)
- FM waveform, modulation index, deviation, and bandwidth (Carson's Rule)
- Narrowband and wideband FM
- FM modulator circuits: direct (VCO/varactor) and indirect (Armstrong) methods
- FM demodulators: Foster-Seeley discriminator, ratio detector, PLL detector
- FM limiter stages and capture effect
- FM transmitter and superheterodyne FM receiver block diagrams
Phase-Locked Loop (PLL)
- PLL components: phase detector, loop filter, VCO
- Linear and nonlinear PLL models
- PLL applications: FM demodulation, frequency synthesis
- PLL frequency synthesizers
Superheterodyne Receiver
- Receiver block diagram: RF amplifier, mixer, local oscillator, IF amplifier, detector, audio amplifier
- Selectivity and sensitivity
- Image frequency and image rejection
- Intermediate frequency (IF) selection
Noise in Communication Systems
- Types of electrical noise (thermal, shot, flicker)
- Noise figure and noise temperature
- Noise effects on AM and FM receivers
- Signal-to-Noise Ratio (SNR) analysis
Multiplexing
- Frequency Division Multiplexing (FDM) principles
- FM stereo multiplexing
Laboratory Exercises
- Use of oscilloscope, signal generator, spectrum analyzer, and digital multimeter
- AM transmitter and receiver circuit construction and measurement
- FM transmitter and receiver circuit construction and measurement
- PLL circuit characterization
- Troubleshooting communication circuits with introduced faults

Optional Topics

Single Sideband (SSB) and Double Sideband Suppressed Carrier (DSB-SC) modulation and demodulation
Vestigial Sideband (VSB) modulation; application to analog television
Balanced modulators and product detectors (Costas loop)
Pre-emphasis and de-emphasis filters in FM broadcast
Transmission lines: characteristic impedance, SWR, impedance matching
Antenna types, gain, radiation patterns, and propagation modes
Satellite communications: orbital mechanics, uplink/downlink, transponders
Introduction to digital modulation schemes (ASK, FSK, PSK) as a bridge to digital communications

Resources & Tools

Laboratory Equipment

Dual-channel oscilloscope (analog or digital storage)
Spectrum analyzer (hardware or software-defined, e.g., RTL-SDR + SDR#)
RF signal generator with AM/FM modulation capability
Digital multimeter (DMM)
DC regulated power supply
FACET analog communications training board (e.g., Lab-Volt/Festo Didactic 91018) or equivalent bread-board kits

Software & Simulation

Multisim or LTspice — for circuit simulation of oscillators, modulators, and filters
MATLAB/Simulink — signal analysis and modulation waveform visualization (optional)
SDR# (SDRSharp) with RTL-SDR dongle — real-world FM reception and spectrum observation
GNU Radio — open-source signal processing and modulation demonstrations

Career Pathways

Completion of EET2323C supports preparation for careers in electronics and communications technology. Graduates of programs that include this course typically pursue roles such as:

Electronics Technician — manufacturing, testing, and maintaining electronic communication equipment
RF Technician — installation, alignment, and repair of radio frequency systems and broadcast equipment
Communications Systems Technician — supporting two-way radio, cellular, and land-mobile radio infrastructure
Avionics Technician — maintaining aircraft communication and navigation electronics
Broadcast Engineer — operating and maintaining AM/FM radio and television transmission equipment
Field Service Technician — on-site installation and troubleshooting of communications systems
Electronics Engineering Technologist — supporting engineering design and test teams (pathway toward B.S. in Electronics Engineering Technology)

This course is a core component of the Associate in Science (A.S.) in Engineering Technology, Electronics Specialization offered at Florida State College System institutions. With careful planning, the A.S. degree can articulate into bachelor's programs including the Electronics Engineering Technology B.S. at multiple Florida colleges.

Special Information

Certification Preparation

FCC General Radiotelephone Operator License (GROL) — Content in this course (AM/FM modulation, transmitters, receivers, noise, antennas) directly supports preparation for the FCC GROL exam (Elements 1 and 3), which is required for employment in many commercial broadcast and maritime communications roles.
ISCET Associate CET (Certified Electronics Technician) — Communications is a core knowledge area tested in the ISCET Associate-level CET examination. Course content aligns with the Communications subsection of that exam.
ETA International Communications Technician Certification — Students may use course knowledge as foundation preparation for ETA-I technician-level communications certifications.

ABET/TAC Alignment

This course supports program outcomes required for ABET Technology Accreditation Commission (TAC) accreditation of Electronics Engineering Technology programs, specifically outcomes related to applying circuit theory and electronic principles to communications systems, and the ability to use appropriate test equipment and software to analyze electronic systems.

Lab Safety

Students working with RF transmitter circuits must comply with FCC Part 15 regulations regarding unintentional radiators and avoid operating unlicensed transmitters outside of shielded laboratory environments. High-voltage RF power amplifier stages require adherence to standard electrical safety procedures.