Double Sideband-Suppressed Carrier Modulation
Summary
The objective of this activity is for students to apply concepts from Fourier analysis and amplitude modulation with skills in Simulink to create a DSB-SC (double sideband-suppressed carrier) modulator and coherent detector. Students are provided specifications for the message and carrier signals. Students are responsible for designing and testing the modulator and detector systems in Simulink. Students will use the Simulink systems to perform homework problems with more advanced message signals.
CollapseLearning Goals
Students should describe what happens to the spectral content of the message, carrier, modulated, and demodulated signals. Students transform the general equation of a DSB-SC signal and a coherent detector into a Simulink block diagram.
Simulink allows students to visualize the input and output signals of each subsystem. Additionally, building the systems in Simulink reinforces the rationale for both the modulation and detection schemes.
This activity requires students to recall and apply the basic equations for DSB-SC modulation and coherent detection; students must assess results and confirm from Simulink simulation using their knowledge of Fourier analysis.
Simulink allows students to visualize the input and output signals of each subsystem. Additionally, building the systems in Simulink reinforces the rationale for both the modulation and detection schemes.
This activity requires students to recall and apply the basic equations for DSB-SC modulation and coherent detection; students must assess results and confirm from Simulink simulation using their knowledge of Fourier analysis.
Context for Use
This is a junior or senior level course at a small, liberal arts university. The course is an electrical engineering elective where students learn the fundamentals of electrical communications.
In-class activities are performed in a think-pair-share approach. The activities require students to transform the modulation/detection schemes they learn into Simulink models. In-class activities all use single-tone message signals to allow for easy verification and debugging for students. The Simulink models designed in class are then used by students at home for more sophisticated message signals. In-class activities are generally not assessed; homework is assessed with an in-class demonstration.
This is a second or third encounter with MATLAB for students. However, this is the first encounter with Simulink.
In-class activities are performed in a think-pair-share approach. The activities require students to transform the modulation/detection schemes they learn into Simulink models. In-class activities all use single-tone message signals to allow for easy verification and debugging for students. The Simulink models designed in class are then used by students at home for more sophisticated message signals. In-class activities are generally not assessed; homework is assessed with an in-class demonstration.
This is a second or third encounter with MATLAB for students. However, this is the first encounter with Simulink.
Description and Teaching Materials
This activity is done after a 10-15 minute mini-lecture about DSB-SC modulation. Students are asked to perform a think-pair-share. At the end of the lecture, the class reviews the results and discusses the questions included in the activity.
Double Sideband-Suppressed Carrier Modulation (Acrobat (PDF) 239kB Sep7 21)
Double Sideband-Suppressed Carrier Modulation (Acrobat (PDF) 239kB Sep7 21)
Teaching Notes and Tips
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Assessment
As with any group work done in class, some students may become distracted by conversation and alike; emphasizing that the developed systems can be utilized on the homework or requiring submission for a nominal grade can encourage students to stay focused.