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Lee Deborah Lopez William Thompson William

This is very good as an instructive video, but I think there are two errors that you make and need to correct. First is the comment that 50 ohm cable is for low loss applications. That is not true. Most 50 ohm coax such as RG8 or RG213 is rather high loss cable compared to 75 ohm coax, such as RG6, and particularly compared to higher impedance non-coax cable such as 450 ohm window line. This is because the for a given power level, the current levels will be higher in 50 ohm coax vs. higher impedance transmission line, and thus I^2R losses are usually higher, especially if there are standing waves present due to load impedance mismatch. The loss data of coaxial cables and parallel conductor cables are well documented, and are readily found online from coax manufacturers or in texts such as the ARRL Antenna Book or ARRL Handbook. Second, you say that there is no reflection if the load impedance is less than the cable impedance. That is not true either. Any impedance mismatch causes reflected power in the form of reflected voltage or current waves. For smaller load impedance, part of the voltage wave is reflected out of phase relative to the incident wave to partially or fully cancel the voltage wave in order to adjust the voltage/current ratio in the lower impedance load to a smaller value (thus smaller impedance). The ultimate being a short circuit termination, where 100% of the voltage wave is reflected 180 degrees out of phase in order to cancel the voltage to zero at the termination. The reverse is true for an open circuit termination. Mismatch of any kind causes signal loss due to reflected power being consumed by lossy cables. These points can be confirmed by looking up any text on the subject. Also, just a suggestion: it is always more pleasant to hear a real human voice and not an AI created robot voice in these videos.

exceptional work!

This video is significantly just "technical bologna". There is no better or nicer way to describe the technical contents of this video. This video represents everything that is wrong with Internet and RUclips as a learning resource. 1.) The claim half the power reaches the load is completely false. 100% of generator power can reach the load, less cable losses. It can be a very large percentage reaching the load even with a mismatch. 2.) If the generator is conjugately matched to the cable input impedance, even if the cable is mismatched to the load, almost 100% of source power can reach the load. An example would be open wire fed doublet antennas, where the feedline operates with 10:1 or higher mismatches yet nearly 100% of transmitter output power excites the antenna. I often run antennas with 2:1 and higher mismatches and yet the transmission line is highly efficient and the transmitter is perfectly fine. As a matter of fact reflected power does not make it back into normal PA stages. This is easily proven. 3.) Any mismatch causes STANDING waves. Standing waves stand. Standing waves do not bounce around, if they did we would call them "bouncing waves" and not call them STANDING waves. 4.) Standing waves cause an operating impedance variation along the transmission line. That operating impedance, the ratio of across to through vectors, varies with distance along the line. This is how Q-sections and stubs work. Look up Q-sections. They can operate with nearly infinite standing wave ratio yet have high efficiency. We are heading for problems when RUclips becomes our source of education.

The slide at 1:40 is simply wrong. The only time there is NO reflection is when the load perfectly matches the load. The idea that Zload < Zcable causes loss and not reflection casts doubt on the whole of this presentation, as it is a fundamental misunderstanding of how transmission lines behave. In the ideal case where the transmission line has no loss, then there can be no loss as a result of standing waves set up through a mismatched load - there is simply no where for the power to be lost, power is simply energy per second and energy cannot be created or destroyed. When the load impedance is a perfect match for the source impedance, then there are no standing waves, since there are no reflections that would cause them to be set up. Sorry, but the fundamentals of this presentation are wrong. For a robust explanation of transmission lines and standing wave behaviours, see Walt Maxwell's books "Reflections".

Could any one say why they have not considered the Zc (Cable Impedance) in Equation @2:23. Is it because it is neglible compare to Zs and ZL

Cables are recognized by the chipsets, usb cables have resistors, capacitors, chip inside the plug.

What's the name of that simulator?

In 1:37 it is stated that NO REFLECTION happens when ZL < ZC.......Guess that's wrong, in every mismatch there is reflection to my knowledge!? (i.g. a short -in extreme- also will produce a 100% reflection)

What i don't understand is the explanation of the signal relfexion when there is an open circuit, why would a signal travel through a place where there is no end , in circcuits no current flows through a dead end cable.

Much appreciated sir 😊

🙏💐

🙏💐💐💐

Aliasing doesn't cause digital images to look blurry. It causes them to look jagged. In the example with the blurry text, that is actually where anti-aliasing has been applied. The blurring is intentional to avoid the jaggedness, and although it looks blurry when zoomed in, it looks better than aliasing when zoomed out.

In four minutes you have pushed me several points closer to passing my final! Thank you

Awesome visual aids, I wish the textbook I'm reading used these

Many of the examples in this clip is not aliasing, so better to look for other videos if you want learn what it actually is.

Of course you have reflection when Zload < Zcable. There is only one way to not have reflection and that is to not have a mismatch. Reflection causes VSWR which proves that you are wrong in your statement. If you don't believe me then try to terminate a 50 ohm coax with a 25 ohm resistor. You will get VSWR close to 2 with a reflection coefficient of 1/3 and a reflection angle of 180 degrees. 11% of power is reflected. If you change out the 25 ohm resistor with a 100 ohm resistor the results are almost the same. Only difference is the reflection angle which now is 0 degrees.

We need more such type of Analog circuit video........

What about impedance mismatch in differential pair configuration ? Please

Thank you stephen hawking

Great explanation, thank you. ^_^

Let's use DA-AD conversion for re-sampling to keep steepness origin. Comparator operational amplifier can do it. Math-algorithmical ones(interpolation,LPF) creates global nonsenses even in audio. There is a many records, especially in movies, that combine 44100Hz music with 48k-192k sounds and dialogs. And its bad, when they using virtually re-computed signals in mixture. Class-A signal processing is the only way.

sir, human hear sound range in 20 to 20Khz is travel distance 180m,video 1min:53sec, how to 5khz voice travel in 8km.

Nah bro, AM and FM should keep on living just because there's radio .edit also great vid

Great info in a short video. Loved it.

Most helpful video

Very nice video

What TTS voice is that - I like it. Reminds me of the joke by Stephan Hawking, "yo mama so fat her escape velocity exceeds..."

Why do the most profound subjects get so few views? Thank you for the upload.

Explain the conversion in detail.

Bullshit! Aliasing is very, VERY useful. ruclips.net/video/6MFLAe3YJf8/видео.html

Could you use this to explain bandwidth, for example the frequency range which the high pass filter has sufficient gain on the input?

Why are frequencies not in the bandwidth not transmitted via the channel? Is it because every channel has its own capacitive/inductive qualities? From my limited knowledge, I know except for the resistor, the impedance changes with the frequency.

😂I don't like the robotic voice

Cable impedance is low as compair to transmission line but how can cable reflect the surge voltage generate in line due to fault

the first FfT based sa...! does that mean there's also SA that don't use FFT ?

Say you received a Signal with to much amplitude - or to much noise floor within your intended signal. How can you plot out the Frequency amplitude as it was intended? how would you fix x-y Amplitude of a signal as. How do you know how much amplitude a intended signal was

well, at least I can't hear your accent...

Very excellent

👍👍👍

Super clear and straight to the point, thanks.

But this voice :/

that was great thank you

I love it when Robocop teaches me something new...

Damn it i understand the whole context by just listening to the first sentence. Thanks

Nothing worse than these computer generated voice!!!!!!!

How do we measure the impedance of the "load" and the cable without an oscilloscope? information not provided by the manufacturer!

"Adding a resistor in series with the source or the load, or using a termination resistor is a basic method to achieve impedance matching." - also incorrect. A conjugate match the most common method.

"There is no reflection when the load impedance is smaller than the impedance of the cable." - also incorrect.