Thank you so much for your video easy to understand. May I ask you a question? I'm junior of electronic engineering. I'm interested in digital communication especially MIMO. So I want to study watching your video. but I don't know what to watch first. I have learned "signals and system" previous semester, and learn about AM/FM on "communication system" in this semester. Could you recommand sequence of studing digital communication? thank you.
Great to hear that you're interested to learn. Have you seen my webpage? It lists all of my videos categorised in a logical order. iaincollings.com Also you can watch the Playlists on my RUclips channel where I have grouped the videos too.
One of the best videos I saw for SFCW: Could you please tell me when applying IFFT over a set of complex numbers generated by aNSFCW radar, how many points describe the signal in time. For, if my frequency sites are 4096, I must have 4096 points when applying IFFT. Now we know the signal propagated based on the time for each step, meaning the total time / 4096 steps. Can we apply UFFT only on one of these complex numbers and expect to see the reflection related to that specific frequency? Or we should always apply IFFT over the set of complex numbers, and therefore, we have a number of points in the time domain or sample points equal to the number of steps.
Hopefully this video helps: "How does the Discrete Fourier Transform DFT relate to Real Frequencies?" ruclips.net/video/pIFz84oj9cA/видео.html and you might like to watch some of my other related videos on the DFT (which is what the FFT implements) which can be found on my webpage under the Signals and Systems tab iaincollings.com
How to apply this in Fmcw where Doppler is also measured and processed. This r0 phase changes from chirp to chirp but so does the doppler phase 2pi 2 df × n v /c nT + 2pi 2 f0 v /c nT Answer is much appreciated
Time and Frequency domains are linked by the Fourier Transform (time-to-freq) and the Inverse Fourier Transform (freq-to-time). More details on how they are related is here: "Fourier Transform and Inverse Fourier Transform: What's the difference?" ruclips.net/video/N8RV6WT4sTY/видео.html
Thank you for your wonderful educational videos. I want to know how OFDM waveforms can be used for radar operations? also what is Ambiguity function and why used as a metric for radar signals?
Using OFDM in a radar is a bit like sending a stepped frequency waveform, except all of the different frequencies are being sent at the same time. And thanks for suggesting the Ambiguity Function as a topic. I've put it on my "to do" list.
thanks Professor Collings for your fascinating signals and systems tutorial encyclopedia. I had an off topic question 🙈 what is the model for your Parker pen? (I really like your pen selection and I think educating on paper is the best method ever)
Glad you like the channel. The pen is a Sonnet model Parker, and I can highly recommend it - very nice to hold and write with. And I'm very glad you like the approach of using pen and paper in the videos. Some people have described it as "non-tech old-school", but I agree with you - it's the best way to explain things.
@@iain_explains thanks, I will give it a try! and after being years in school, I always recommend the students to first accept to hold a pen and organize their thoughts on the paper instead of just fighting with software for problem solving.
Welp time to check the FT formula sheet again... 7:23 Can you do a follow-up video on aviation radar then? Would the British engineers of WWII have faced the same issue as this? Also thanks for teaching me signals! These videos mesh well with what I was taught in class in terms of difficulty.
Thanks, yes I've already got the airborne radar topics on my "to do" list. I'm not sure what exact waveforms were used when they were first developing radar in WWII.
For almost all cars built in the past 10 years, when they reverse, they use radar from the sensors in the bumper bar, and they beep if objects get too close. And modern cars use radar out the front of the car to do adaptive cruise control, by working out how far it is to the car in front, and whether the car in front is slowing down or not. That's just two examples.
@@iain_explains Oh this is so interesting, when I think of radar I always think of those large parabolic disc in the SETI project. I dont have a car so I never know that they could integrate that thing into a car hahah
Nice lecture~! I love it. Is this suitable for airborne ground penetration radar?
Glad you liked the video. And yes, GPR uses stepped frequency.
Thank you so much for your video easy to understand.
May I ask you a question? I'm junior of electronic engineering.
I'm interested in digital communication especially MIMO. So I want to study watching your video. but I don't know what to watch first.
I have learned "signals and system" previous semester, and learn about AM/FM on "communication system" in this semester.
Could you recommand sequence of studing digital communication?
thank you.
Great to hear that you're interested to learn. Have you seen my webpage? It lists all of my videos categorised in a logical order. iaincollings.com Also you can watch the Playlists on my RUclips channel where I have grouped the videos too.
Thanks for your advice!
I didn't know about the website. I'll visit your website.
Have a good day:)
One of the best videos I saw for SFCW: Could you please tell me when applying IFFT over a set of complex numbers generated by aNSFCW radar, how many points describe the signal in time. For, if my frequency sites are 4096, I must have 4096 points when applying IFFT.
Now we know the signal propagated based on the time for each step, meaning the total time / 4096 steps. Can we apply UFFT only on one of these complex numbers and expect to see the reflection related to that specific frequency? Or we should always apply IFFT over the set of complex numbers, and therefore, we have a number of points in the time domain or sample points equal to the number of steps.
Hopefully this video helps: "How does the Discrete Fourier Transform DFT relate to Real Frequencies?" ruclips.net/video/pIFz84oj9cA/видео.html and you might like to watch some of my other related videos on the DFT (which is what the FFT implements) which can be found on my webpage under the Signals and Systems tab iaincollings.com
How to apply this in Fmcw where Doppler is also measured and processed. This r0 phase changes from chirp to chirp but so does the doppler phase 2pi 2 df × n v /c nT + 2pi 2 f0 v /c nT
Answer is much appreciated
Also what if one uses DFt (or fft) instead of iDft (ifft), I don't see the explicit necessity gor iDft
Time and Frequency domains are linked by the Fourier Transform (time-to-freq) and the Inverse Fourier Transform (freq-to-time). More details on how they are related is here: "Fourier Transform and Inverse Fourier Transform: What's the difference?" ruclips.net/video/N8RV6WT4sTY/видео.html
Thank you for your wonderful educational videos. I want to know how OFDM waveforms can be used for radar operations? also what is Ambiguity function and why used as a metric for radar signals?
Using OFDM in a radar is a bit like sending a stepped frequency waveform, except all of the different frequencies are being sent at the same time. And thanks for suggesting the Ambiguity Function as a topic. I've put it on my "to do" list.
thanks Professor Collings for your fascinating signals and systems tutorial encyclopedia.
I had an off topic question 🙈 what is the model for your Parker pen?
(I really like your pen selection and I think educating on paper is the best method ever)
Glad you like the channel. The pen is a Sonnet model Parker, and I can highly recommend it - very nice to hold and write with. And I'm very glad you like the approach of using pen and paper in the videos. Some people have described it as "non-tech old-school", but I agree with you - it's the best way to explain things.
@@iain_explains thanks, I will give it a try! and after being years in school, I always recommend the students to first accept to hold a pen and organize their thoughts on the paper instead of just fighting with software for problem solving.
Welp time to check the FT formula sheet again...
7:23 Can you do a follow-up video on aviation radar then? Would the British engineers of WWII have faced the same issue as this?
Also thanks for teaching me signals! These videos mesh well with what I was taught in class in terms of difficulty.
Thanks, yes I've already got the airborne radar topics on my "to do" list. I'm not sure what exact waveforms were used when they were first developing radar in WWII.
plz if you have any document about Fractionally Spaced plz send to me
Do people actually use radar in day to day application or it just something that come out from a war ?
For almost all cars built in the past 10 years, when they reverse, they use radar from the sensors in the bumper bar, and they beep if objects get too close. And modern cars use radar out the front of the car to do adaptive cruise control, by working out how far it is to the car in front, and whether the car in front is slowing down or not. That's just two examples.
@@iain_explains Oh this is so interesting, when I think of radar I always think of those large parabolic disc in the SETI project. I dont have a car so I never know that they could integrate that thing into a car hahah
SETI doesn't use radar. It only receives signals. It doesn't transmit anything.
@@iain_explains Oh so that is how it works. My mistake
Am*exp(-j PHI) -> fft; Am*exp(+j PHI) - > ifft
Yes. Here's a video on that point: "Fourier Transform and Inverse Fourier Transform: What's the difference?" ruclips.net/video/N8RV6WT4sTY/видео.html