Hi, my name is Brad Jolly, and I'm an Applications Engineer here at Keysight Technologies.
In this video I will discuss four charts for fast IoT device battery life insights with
the Keysight X8712.
In this video we'll go over the table, the markers, and all of the charts in great detail
to make sure that you understand exactly the benefits you get from seeing the different
charts.
So again, if you go to the zoom chart here – and let's turn off the others – this
lets you see the time slicing that's going on.
And if you look in there, you can see the green is the RF, the pink is the active current,
and the sleep is the tan color here.
And again, that's all based on the position of these markers here.
So I can put the markers wherever I want.
And it doesn't matter.
There's no sense of left or right.
There's just everything between the markers.
And then I can reanalyze.
And when I reanalyze the data, it will show me exactly what I'm looking at there.
And then I can zoom in even further if I so desire.
And then double-click will take me all the way back out.
And notice that that corresponds to the area around these markers.
Similarly, I could say, well, I just want to look at my sleep current in detail and
reanalyze.
And this should be everything in a nice tan color with no green or pink.
And notice that it's zoomed in very heavily, so that's why you’re seeing this what appears
to be noise here.
A typical thing that you would do is look at an integer number of cycles.
So you might go from here to here, which appears to be two full cycles, and then analyze it.
And you – again, you'll see the zoom showing you those two full cycles.
Now, in addition to the zoom, you've got the ability to do a current consumption graph.
Okay.
And that will give you the charge consumption by mode.
So 31 percent is in these RF spikes.
66 percent is in active current in addition to the RF spikes.
And then three percent is in this sleep mode.
You can also look at it in terms of time.
Okay.
So there it is in terms of time.
You can look at them both at the same time.
And you can then, of course, reanalyze or whatever you want.
So if you look at a very active segment here, and then reanalyze, you'll notice that the
– both the bar and the pie charts adjust accordingly.
And then the final chart that you've got is this CCDF chart.
CCDF stands for complementary cumulative distribution function.
So let me describe what that is.
Let me go ahead and set it up to a more typical sort of value.
And then analyze.
And you'll notice it starts up near 100 percent.
Let me look here, and you'll see it says at one microamp, Y is 94.
So what that means is that 94 percent of the time, I am at one microamp or higher.
That's 94 percent of the time.
So that tells me that about six percent of the time I am at currents below one microamp.
Now if I move my mouse over here to four microamps, that's down to 64 now.
So you recall that it was at 94 at one microamp, and now it's at 64 for four microamps.
So that tells me that 30 percent of the time, I am between one and four microamps.
And then if I go all the way down here down to ten microamps, right over here – just
a matter of – there we go – ten microamps, I'm down to seven.
So what that tells me is that one microamp I was at 94 percent.
At ten microamps I'm only at seven percent.
So that tells me that 87 percent of my current consumed in two typical full cycles is consumed
between one and ten microamps.
And the basic idea here is what you're trying to do is you're trying to push this graph
down and to the left.
So what you would do is you'd take a screenshot of this and then make your changes to your
firmware, reanalyze things, and see if the graph moved basically down and to the left
because that's what you want to do to increase battery life.
So for example, let's pretend that I was able to get the device to where it was almost always
sleeping.
Okay.
So if you look at this here, and we reanalyze here, okay, see how it went down to the left?
And if you get down here to ten microamps, it says only one percent of the time – two
percent of the time at ten microamps are you above ten microamps.
So you see that it went down and to the left.
Similarly, if we – let's suppose we were like this, where we are in a very active mode.
Let's reanalyze.
And we would expect it to go up and to the right.
And that's exactly what it does.
Okay.
And so what you're trying to do is over time push it down and to the left.
And of course, you don't want to do that just by moving the markers.
That's kind of fraudulent.
What you want to do is say, okay, what can I do in terms of adjusting my hardware and
firmware programming so that my CCDF legitimately moves down and to the left.
So that's what that's all about.
Thank you for watching.