At 4:56 there is a bit of simplification -> if x and y are in dB, then: log(x+y)=log(10*log(x)+10*log(y))=log(10*log(x*y)) which doesn't mean it is usefull in practice
Very nice video. One thing I noticed. A 12:44 you say: "the spectrum analyzer is telling you what the power is..." Doesn't it show the voltage of the spectrum? It it would, as you say, show the power there is no need to convert it to the power in 50 Ohms...
632mV=0.632V power=0.998mW...1mW approximately.... prof. your calculation is wrong at 12:16... you cannot square 632mV which will result in 632^2* (10^-3)^2 V which is wrong... convert to Volts first then square the voltage
No, the calculation is correct. He has squared the 1/2 and the 1/sqrt(2) terms indefinitely, which together equals 1/8. Then, he squared the 623 mV term. Finally, he multiplied them together. It is simply a shortcut to avoid having to divide by root 2
I know this is quite old, but the correct answer is 998 mW. Sure, when squaring millivolts you end up with microwatts, but 632^2 gives you 399424 or 399.424 x 10^3, which multiplies with microwatts to get milliwatts.
@@gvcallen lol... I don't even remember anything anymore about that.... I graduated a year ago and am currently working in the field of embedded systems/FPGAs 🤣
You really mess up the whole concept of dB and dBm; you have made this look more complicated. Where is the dBc concept? If you do not know something do not try to make things up worst.
