Plot native C++ signal buffers while the Visual Studio debugger is stopped. Point it at a std::vector, an array or a raw pointer. The plots are recalculated from the buffer's current memory at every break.
You don't change any code, add probes or rebuild your project.
Quick start
Say your program has a buffer of samples:
std::vector<std::complex<float>> samples(4096);
// ... fill samples ...
__debugbreak(); // or set a normal breakpoint on the next line
- Debug the program (F5) and let it stop after the buffer is filled.
- Right-click
samples in the code editor and choose Plot in Waveform Watch. You can also open Tools > Waveform Watch and type samples in Buffer.
- Under the watch list, enter the Sample rate (Hz), for example
30.72M, and press Enter.
- Continue or step. The plots update at every break and keep your zoom.
- Click Hold as reference to keep a snapshot. It is drawn in grey under later breaks, so you can compare before and after.
Click Help in the window, or choose Tools > Waveform Watch Help, for the full guide.
What you can plot
| Expression |
Use for |
samples |
std::vector, std::array or a C array |
ptr, count |
A raw pointer, for example m_I_buffer, m_blockSize |
iPtr, n ; qPtr, n |
Separate real I and Q buffers |
spec |
A struct holding the data with its start and spacing. Waveform Watch finds the members by name. |
- Real:
float, double, 8/16/32-bit integers.
- Complex:
std::complex<float>, std::complex<double>, Ipp32fc, Ipp64fc, Ipp16sc, Ipp32sc.
- I/Q pairs: a real array whose values alternate I and Q.
Number fields take plain numbers, suffixes (30.72M, 1u, 2.4 GHz) or debugger expressions such as m_sampleRate.
Views
| Tab |
What it shows |
| Time - Volt |
I, Q and |x| in volts against time. Long buffers keep their peaks. |
| Freq - Amp |
Amplitude spectrum in dBV or V. Averaged (Welch), single unscaled FFT as the LabVIEW probe plots it, or pyprobe-compatible. |
| Freq - Phase |
Phase against frequency |
| Statistics |
RMS, peak, PAPR, mean power, DC offset, I/Q ranges and the sample values |
| Power |
Instantaneous power in dB or dBm (50 ohm), with the mean as a dashed line |
| Constellation |
I against Q on equal axes |
| CCDF |
Probability that power exceeds the average by x dB, with a Gaussian reference |
| Trend |
RMS, peak, mean power or PAPR at each debugger stop |
| History |
Captures from earlier stops, which you can show, overlay, export and import |
Analysis features
- Plot controls: type axis ranges, lock an axis, choose line or points, and place two markers that snap to the trace and read out the difference between them. Settings are kept per watch and per tab.
- Compare watches: overlay up to three watches on the selected one, or plot their difference.
- Trend and history: follow a statistic across breaks and keep captures to compare a stop with an earlier one, even when the program isn't at a break.
- Capture export and import: save a capture to a
.wwcap file to share. It holds sample values only, never code.
- Recipes: save a whole setup (watches, units, axes, markers) to a JSON file and load it later or on another machine.
Zoom with the mouse wheel, pan by dragging, and zoom into a region with the right mouse button. Press A in a plot to reset it.
Good to know
- The program must be debugged on the same machine. Remote debugging isn't supported.
- Each plot shows the buffer exactly as it was at that break. If code processes a signal in blocks, you see only the current block.
- Buffers are read up to 16,777,216 samples and shown as 32-bit float volts (peak).
- History is kept in memory only: up to 20 captures per watch and about 256 MB in total.
std::vector is read straight from memory, so no code runs in your program.- Child rows in Watch, Locals and Autos, such as
[0], can't be plotted with right-click. Type the full expression instead.
- If the menu items are missing, close Visual Studio, run
devenv /updateconfiguration from a Developer PowerShell and start it again.
Waveform Watch Lite is a smaller edition with the time, spectrum, phase, statistics, power, constellation and CCDF views, without the analysis features above. Both can be installed together.
Requirements
- Windows x64 with Visual Studio 2022 (17.x, any edition) and the C++ workload.
Release notes
1.2.0
- Added in-product help (Help button and Tools > Waveform Watch Help) and a hint in the empty window.
- Capture export and import in the History tab, and faster marker snapping on very large spectra.
1.1.0
- Plot controls, overlays and difference, trend and history, and recipes.
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