Waveform Viewer

Waveform viewer

The waveform viewer is the large plot on the right of the ChipWhisperer Studio window. It shows every trace as it is captured, lets you overlay and average traces, browse stored traces, zoom, and measure with two cursors.

The toolbar at the top controls what is drawn; the footer below the plot shows statistics of the displayed trace.

The viewer is visible on every tab except Notebook, which uses the main area for its cells (see Notebooks). Traces captured by notebook code still appear here when you switch back.

Toolbar

Control	What it does	Default
Source	Live (latest capture) shows each new trace as it arrives. Browse stored traces shows one stored trace at a time, chosen with the # number box or the slider next to it.	Live
Overlay	Draws the last 5, 10, 25 or 50 live traces behind the current one, fading older traces. Use it to see how stable your traces are: well aligned traces overlap tightly. Overlay collects traces from the moment you turn it on.	no overlay
mean	Draws the average of all stored traces.	off
min/max	Draws a shaded envelope between the lowest and highest value of all stored traces at every sample.	off
auto Y	Rescales the vertical axis to fit each trace. Turn it off to keep the vertical scale fixed while traces update.	on
time axis	Labels the horizontal axis in time units instead of sample numbers, using the ADC sample rate read from the scope's clock settings (it follows clock changes made anywhere, including notebooks and agents). If Studio does not know the sample rate, the axis keeps showing sample numbers.	off
code	Shows the code band under the plot: which firmware functions and source lines run when. Needs a code map (Code tab); it switches on by itself after a build.	off
Pause / Resume	Freezes the display while captures continue in the background. Also on the Space key.	running
Zoom in / Zoom out (magnifier buttons)	Halves or doubles the visible range of samples, centred on cursor A when it is in view, otherwise on the middle of the view. The + and - keys do the same.
Fit	Resets the zoom to show the whole trace. Double-clicking the plot does the same.
Cursors	Removes both cursors.
PNG	Saves the current plot as trace.png, with a background matching the current theme.

The mean and min/max statistics are computed over all stored traces. They are refreshed when a capture finishes and when you turn them on, not after every single trace.

Zooming

• Drag horizontally across the plot to zoom into that range of samples.
• Press the zoom in and zoom out buttons (or the + and - keys) to zoom in steps of two around cursor A or the middle of the view.
• Double-click or press Fit to zoom back out.
• Ctrl+drag (Cmd+drag on macOS, or Alt+drag) does not zoom: it picks a sample range for the code map.

While you are zoomed in, new live traces keep your zoom. The use zoom button in the Analysis tab copies the zoomed range into the attack's sample range, so you can attack only the part of the trace you are looking at.

Cursors and measurements

Cursor A (pink) and cursor B (purple) with the difference shown in the footer.

• Click the plot to place cursor A.
• Shift+click to place cursor B.
• Cursors in the toolbar removes both.

With both cursors placed, the footer shows:

Read-out	Meaning
A #n=v, B #n=v	Sample index and value at each cursor.
Δ n samples	Distance between the cursors in samples.
= t (f Hz)	The same distance in time and as a frequency (1 divided by the time), when the sample rate is known. Handy for measuring how long an operation takes or the period of a repeating pattern.
ΔV	Difference in value between the two cursors (in the scope's normalised units).

Moving the mouse over the plot also shows a hover read-out with the sample index, value and time under the pointer.

Tip: The Calculator can compute the mean, RMS, peak to peak and more for the samples between the two cursors: choose Waveform: between cursors A and B as the source.

Footer

The footer under the plot describes the displayed trace:

Field	Meaning
live #n or trace #n	The trace's index in the trace set, or "not stored" if store traces was off.
samples @ rate	Number of samples and the sample rate in MS/s (when known).
min, max, pk-pk, mean	Statistics of the displayed trace.
pt, ct, key	The plaintext sent, the ciphertext received and the key used for this trace, in hex.

Keyboard shortcuts

Key	Action
S	Capture a single trace (not while a notebook has the focus)
R	Run a capture (not while a notebook has the focus)
Esc	Stop the running capture or sweep
Space	Pause or resume the display
Left / Right	Previous or next trace (in Browse mode)
+ / -	Zoom in or out around cursor A

Shortcuts are ignored while you are typing in a text box.

Performance

Captures can run much faster than a screen can redraw. Studio sends at most Display fps traces per second (25 by default, set in the Capture tab, see Capturing Traces) to the viewer and always sends the final trace of a run with a fixed trace count, while every trace is still stored. Traces travel to the browser as compact binary data, and the plot uses the uPlot library, so traces with tens of thousands of samples stay smooth.

See also

• Capturing Traces for recording traces.
• The Analysis tab, whose overlay corr option draws the correlation of a key byte on top of the waveform.
• Interface Tour for the rest of the window.