Essentials of Signals & Systems: Part 2

[@AM-tu1rc]

No one explains Signals & Systems as well as you do Professor! You give an excellent blend of both theory and examples to condense complex concepts into the core fundamentals.

[@iain_explains]

Thanks for your nice comment. I'm so glad you like the approach I've taken to explain the concepts.

[@uncleroq]

Thanks for the upload Professor. Signals and Systems never been more interesting!

[@iain_explains]

I'm so glad to hear that.

[@fifaham]

Thank you very much Iain, very helpful lecture.

[@iain_explains]

Glad it was helpful!

[@ZaidKhan-kv8ok]

Hi Ian sir, most importantly huge gratitude to you for your service to all students who find telecommunication topics challenging. I had a request - can you make an explanatory video explaining each part of an OFDM radio transmitter (and maybe someday similarly Receiver) -> ifft, cp-addition,.dpd-cfr, calibrations, DAC, PAs etc till RF signal generation.

[@iain_explains]

Thanks for the suggestion. I'll add it to my "to do" list. I'm glad you like the channel.

[@leocmen]

Thank you so much for sharing your knowledge wth us. God bless you

[@iain_explains]

You are very welcome

[@divyanshmittal772]

1:00 to 2:00 could anyone please explain in details, How one continuous signal in TD got one output in FD and if sampled in TD then it is repeated in FD. Also please tell me how I can visualize this MATAB

[@iain_explains]

These videos might help: "Sampling Signals" kzbin.info/www/bejne/d5TYgqF_jc6NaKM , "Sampling Signals: Introduction Lecture" kzbin.info/www/bejne/fKXNZKOHot6pq7s , and "Discrete / Fast Fourier Transform DFT / FFT of a Sinusoid Signal" kzbin.info/www/bejne/oqi0hYGZjNmBbdk

[@amitpalkar934]

Excellent professor.

[@iain_explains]

Glad you think so!

[@vsw1131]

I don't know how to send a private message, but after watching your video about the NOMA system, teacher, I want to ask a question: What is the combination of NOMA and OFDM? I put forward such a conjecture: In the case of mutual cooperation between two users in a cell, 16QAM modulation technology is used to modulate the data onto each OFDM subcarrier (and the carriers are orthogonal to each other, there is no mutual interference), and then use NOMA's power multiplexing technology...... I would be very grateful if you could answer my question. thank you!

[@iain_explains]

Yes, you could perform NOMA on each subcarrier.

[@lakshmikandula634]

while converting CT frequencies to DT frequencies , you multiplied all CT frequencies with T except wm. can you please clarify this ?

[@iain_explains]

Sorry, that's a typo. Thanks for letting me know. It should also be multiplied by T.

[@mq6605]

Thank you very useful lecture sir. please may I ask you to do a video about Rake Receiver.

[@iain_explains]

Thanks for the topic suggestion. It's on my "to do" list.

[@mq6605]

@@iain_explains Thank you professor

[@KisoreMuthiahAnnamalai]

If delta function has an infinite amplitude and zero width at t=T making the area 1 when taken across whole time axis, how multiplying it with the signal x(t) provide resultant samples that are of the amplitude x(t=T). Shouldn't it be infinity as the delta function's amplitude is infinite and when multiplied, doesn't the amplitudes get multiplied in the result sir????

[@iain_explains]

Yes, you're right. Sometimes people talk about delta functions as having a "height" (even though the height is actually infinity), since we tend to draw delta functions with heights that relate to their area. If we always drew the delta function arrows the same height, irrespective of their area, then it wouldn't convey the area information, and the graphs wouldn't be very intuitive.

[@daviddima8598]

Hello. With all my respect, but I think there is a mistake when you drew the spectrum of the decimated signal. An N order decimation also implies that the signal spectrum is also expanded in an N factor right? So Wm should be now 2Wm. On the other hand, replicas still repeating every 2pi, not pi I think. Just my two cents 😊

[@iain_explains]

But I didn't draw the decimated signal! You'd be correct, if I'd drawn the "compressed" version of the sampled signal (ie. the "sampled" signal, but with the "zeros" removed). Also, I don't like the term "decimated", since this literally implies removing one sample in every ten. I much prefer to describe the process in two seperate steps - "sampling" and "compression".

[@daviddima8598]

You are totally right!👌

[@adeddy8138]

That actually covers everything thank you sir Except fft part which seens more less intuitive to me

[@iain_explains]

I'm glad you found it helpful.

[@zeroxdan]

thank you for this :)

[@iain_explains]

You're welcome 😊

[@sudiptoshyam]

And as promised On Monday Thanks

[@iain_explains]

😁

[@youssefhamad8164]

❤️😘💯🫶🏼🫵🏽👍👏👏👏