Alright, let's do some math.
So remember, our starting point is always 0 dBm equals 1 milliwatt.
And then we just have to take one of these sides to whatever we were given.
So in this case, we're given 13 decibels.
To get there, we'd say plus 10 and plus 3.
So that gets us to our 13.
Meanwhile over here, plus 10 means that, remember, we multiply by 10 and plus 3
is multiply
by 2.
Our rule of 10s is plus 10 is multiplied by 10. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
Our rule of 10s is plus 10 is multiplied by 10.
Minus 10 is divided by 10.
Plus 3 is times 2.
Minus 3 is divided by 2.
So this would be our set of rules that we're going to use throughout this set
of examples.
So if I'm multiplying 1 by 10, and then by 2, this would be 20.
And so the answer is simply 20 milliwatt.
So let's do the same thing down here.
We start with our 0.
We start with our 1 to get to 24. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
We start with our 1 to get to 24.
I could do a bunch of 3s.
That would be one way to do it.
I could also get to 30 and then go backwards to 27 and then to 24.
So I could say plus 10 plus 10 plus 10 and then minus 3 minus 3.
So this would be times 10 times 10 times 10, which this is 1000.
And then divided by 2 divided by 2.
So that takes me to 500 and ultimately 250 milliwatt. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
So that takes me to 500 and ultimately 250 milliwatt.
Now what if you did the other way?
What if we said, hey, I'm just going to add 3 8 times.
So if I'm adding 3 8 times, that would be times 2 times 2 times 2 8 times.
So that would be 2 to the 8th power, which is 256.
So wait a second, Jeff.
Why doesn't that equal the exact same thing?
And the answer is because even though a plus 10 dBm is exactly equal to a times
10 milliwatt's WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
10 milliwatt's
plus 3 is actually more like 0.1995, something like that.
We actually estimate around a little bit with the rule of 3s.
So the more 3s we use, the more it's going to be a little bit inaccurate with
the conversion.
But for the most part, again, we see it's about the same thing.
A 6 milliwatt difference isn't a major difference.
And so either one of these could be considered the correct answer.
Now from here, 200 milliwatt's to how many decibels.
So now we're flipping it around a little bit. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
So now we're flipping it around a little bit.
I'm going to start with my 1 milliwatt equals 0 decibels.
And I've got to figure out how to get to 200 using these rules.
So if I could get to, let's say, times 10 is 10, times 10 is 100, and then
times 2, well,
that does get me to 200.
And times 10 is equal to plus 10, times 10 is equal to plus 10, times 2 is
equal to plus 3.
And so the answer here is going to be 23. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
And so the answer here is going to be 23.
So 23 dBm.
And then lastly, our 25.
So same concept, I'm going to start with 1 milliwatt equals 0 decibels.
Now I have to get to 25 using 10s and 2s.
But first, this seems kind of impossible. I mean, how do I get from 1 to 25 by
multiplying
by 10 and 2?
I just can't do that.
But in the same way with the decibels, I can go forward and backwards.
For example, I could say times 10 times 10, and then this gets me to 100. WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
For example, I could say times 10 times 10, and then this gets me to 100.
Well, now I can kind of see a path to get to 25, because I could say divide by
2 to get
to 50, and then divide by 2 to get to 25.
So this would be plus 10 plus 10 on the decibel side, and then minus 3 minus 3.
And so at this point, it would be 20 minus 6.
And so the answer here is 14 dBm.
So this is a set of examples that gives us a good look at how to perform our WEBVTT X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000
So this is a set of examples that gives us a good look at how to perform our
decibel math.
And we just need to really keep in mind this table right here.
If we can remember the rule of 10s, remember the rule of 3s, that's going to
help us to
be able to do the conversion, whether we're given a decibel that we need to
convert to millawatts
or vice versa, we're given millawatts that need to convert to decibels.
A decibels.
I hope there's been informative for you, and I'd like to thank you for viewing.