I'm glad you liked it.

If you check out my webpage you'll find a few videos with examples of PDFs, including Gaussian, Chi-Square, ... iaincollings.com

I'm so glad you find the video helpful

I'm glad you liked it.

This is a good video explaining my point: kzbin.info/www/bejne/mHmsmZqulttsgrssi=LvEVq-6zHtSUpZvK

What you're saying is contradictory. The Poynting vector depicts the direction and rate of transfer of energy (ie. power). By definition, when the power is negative, the Poynting vector points in the opposite direction (compared to when the power is positive).

That video you referenced is nice, but don't get too carried away about it. He claims that it's wrong to think that electrons are pumped around a circuit in DC, and back-and-forth in AC. But that's exactly what's happening!!! He even states that they do in fact move (he says "drift") along the wire in the direction given by the battery (at the 6:42 min mark of his video)! Also, he hypes up the idea that energy is "flowing around the wire", not "in" the wire. But this is totally obvious to anyone who uses a mobile phone, wireless radio, or uses a TV with an aerial. Electromagnetic energy is transmitted ("flows") in the electromagnetic wave radiated by electrical antennas, in all of those examples. That's how a mobile phone sends and receives its signals! I'm sure that if he'd pointed out those examples in his video, then everyone would just say: "oh yeah! that's right - electrical energy does flow through the air". But obviously it wouldn't have got as many "clicks/views/likes".

... to be more clear, you're getting confused by AC signals (where half the time the voltage and current are positive, and half the time they are both negative), and thinking that this means that half the time the Power is positive and half the time it's negative. Not true! Negative times negative equals positive. So the power is always positive (in basic resistor circuits). ... It's not always the case though, when there are inductors and capacitors in the circuit - but in these cases the power (and Poynting vector) does actually flow (point) in the negative direction for periods of time! See this for more details: "What is Reactive Power in Electric Circuits?" kzbin.info/www/bejne/fnWkc6WKYr6HgLc

Glad it was helpful!

Glad you liked it

I'm so glad you like the videos.

Let's call it a 'minor typo'. Although it's not really a typo, just an inconsistency. Actually that particular DTFT function is real valued (there is no complex component), so it's a plot of the actual function (rather than the magnitude - which the other plots are).

It’s an engineering specifically signals and systems

I'm glad it helped.

Thanks for the suggestion. It's on the list. 😁

No, neither of those things. As I said in the video, an example is: If an electrical signal has a random voltage (at any given time) with a zero-mean Gaussian distribution, then the signal power has a chi-square distribution (... because Power = Voltage^2 / Resistance ... assuming the resistance is constant). In this zero-mean case, the Variance is the expected value of the power. Which means that in this case, the Variance of the signal (which has a Gaussian distribution) equals the Mean of the power (which has a chi-square distribution).

Glad you liked it.

What do you mean by "real signal"?

I'm glad you like the channel.

That's great to hear.

It's the same reason, except that in this case it's your brain that can't keep up with the rate of change of what your retinas are receiving.

In some cases under-sampling can achieve the ultimate goal (eg. in some cases of digital down conversion), but in general you need to make sure you're sampling at least twice the rate of the change in the signal. You might like this video: "Which Way is the Propeller Spinning?" kzbin.info/www/bejne/pJrcnIN-ZdNngJI