Matlab Examples: Amplitude Modulation and Envelope Detection

http://www.FreedomUniversity.TV. A video describing the concept of envelope detection using Simulink found in Matlab. If you have questions on this video, contact john@e-liteworks.com.

Category:

Education

Tags:

• matlab
• simulink
• amplitude
• modulation
• envelope
• detection
• demodulation
• examples
• tutorial
• tutorials

[skylinknet]

Hi there Prof Santiago, this is really cool. Can you build these circuits for a price? I would like to buy the whole circuit for my laboratory experiments. I do experiments along this line and am thinking of trying out your circuits. Let me know. Cheers!

[drjctu]

@skylinknet Hi skylinknet. No I don't build these circuits anymore...the students built these type of circuits when I taught comm at the USAF Academy about 20 years ago. During that time, I used a 1494 multiplier. Envelope detector as you probably aware of is a diode in series with a parallel combination of an RC circuit. Also, since we have a limited budget at our University, we're using Matlab to demo comm. Good luck in developing your lab experiments. Regards, Dr J

[skylinknet]

@drjctu

Hi Dr J, thanks for your prompt reply. Ok cool. I will try that multiplier. So are you saying that your envelope detector is your series cascade of filters LPF1, LPF2 and LPF3? :-)

[drjctu]

@skylinknet If you lower the message frequency (if it's a pure sinusoidal signal), then it may not be necessary to have a cascade LPFs (a simple RC parallel circuit will act as a LPF). If you need higher order filters then op amps need to be used . Also, to get rid of the dc signal, you need to ac-couple (a capacitor that blocks dc). Hope this helps! Dr J

[syedasaraahmed]

thank you sooo much for posting this vid

[drjctu]

You're most welcome! Dr J

[nedobri]

Why when i start simulation i have error The model DemoAM does not have continuous states what should i do i cant see the signals

[skylinknet]

@drjctu

Hi Dr J, thanks for your reply. I have already built my modulator circuits. Just trying to see if I can get it to the detector stage like your demo. I am just stuck at the filters. Anyway, thanks for your help. You sound like you are very experienced in this. Cheers!

[MrBaghdadboy]

thanks prof but i want to ask you some question about this faculty eleccom eng