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1894027b SA |
1 | == Data Analysis |
2 | ||
3 | Once you have acquired some measurement data, it's time to have a look and see what | |
4 | insights you can gain from it. Usually, the first step is to look at the data as a | |
5 | whole, achieved by clicking the _Zoom to Fit_ button: | |
6 | ||
7 | image::pv_analysis.png[] | |
8 | ||
9 | <1> Zoom-to-Fit button | |
10 | <2> Zoom in/zoom out buttons | |
11 | <3> Cursors | |
12 | <4> Time scale (used to set up and show time markers, see below) | |
13 | ||
14 | If you have located an area of interest (maybe with the help of decoders, more about | |
15 | that later), you can zoom in on it using the _zoom in_/_zoom out_ buttons, using the | |
16 | scroll wheel of your mouse or the pinch/expand gestures on your touch panel. | |
17 | ||
18 | [NOTE] | |
19 | When a data capture is ongoing, the Zoom-to-Fit button stays active if you click it, | |
20 | meaning that PulseView automatically fits all data to the views until either the | |
21 | capture is finished or the Zoom-to-Fit button is clicked again. | |
22 | ||
23 | === Cursors and Time Markers | |
24 | ||
25 | Just looking at the signal data however is usually not sufficient. A lot of times, | |
26 | you'll want to make sure that timings are honored and the bit times are like what | |
27 | you'd expect. To do so, you'll want to use cursors and time markers. | |
28 | ||
29 | In the picture above, you can enable the cursor by clicking on the cursor button. | |
30 | You can move both of its boundaries around by clicking on the blue flags in the | |
31 | time scale area. The area between the two boundary lines shows the time distance | |
32 | and its inverse (i.e. the frequency). If you can't see it, just zoom in until it | |
33 | shows. You can also move both boundaries at the same time by dragging the label | |
34 | where this information is shown. | |
35 | ||
36 | image::pv_cursors_markers.png[] | |
37 | ||
38 | <1> Cursors button, showing enabled state | |
39 | <2> Cursor | |
40 | <3> Time Marker | |
41 | ||
42 | Time markers are static markers that you can create wherever you like on the | |
43 | time scale - just double-click on it and it'll create one for you where your | |
44 | mouse cursor is at the time. You can click on its label and you'll have the | |
45 | option to change its name. | |
46 | ||
47 | [NOTE] | |
48 | For timing comparison purposes, you can also enable a vertical marker line that | |
49 | follows your mouse cursor: _Settings_ -> _Views_ -> _Highlight mouse cursor_ | |
50 | ||
51 | [NOTE] | |
52 | There is also a special kind of time marker that appears for each time the data | |
53 | acquisition device has triggered. It cannot be moved and appears as a vertical | |
54 | dashed line. | |
55 | ||
56 | === Special-Purpose Decoders | |
57 | ||
58 | There are some decoders available that analyze the data instead of decoding it. | |
59 | You can make use of them to examine various properties of the signals that are | |
60 | of interest to you. | |
61 | ||
62 | Their names are: | |
63 | ||
64 | * Counter - counts pulses and/or groups of pulses (i.e. words) | |
65 | * Guess bitrate - guesses the bitrate when using a serial protocol | |
66 | * Jitter - determines the jitter (variance) of a signal | |
67 | * Timing - shows the time passing between the chosen signal edges | |
68 |