Measurements and Cursors

Automatic measurements

The app computes 26 automatic measurements from the captured buffer. They are calculated on the host, not on the microcontroller — the board’s job is to deliver samples, and there is neither the flash nor the SRAM on an ATmega32A to do statistics on top of that.

Measurements cover the usual amplitude, timing and statistical quantities you would expect from a captured waveform. Because they are computed over the buffer, each one describes the samples actually acquired, not a continuously updated running statistic of the signal.

Arranging the panel

The measurement list is drag-reorderable. Put the measurements you use most at the top; the order is yours.

Your selection is remembered between sessions. If you always work with peak-to-peak, RMS and frequency, set that up once and it will be there the next time you open the app.

Measurements are only as good as the buffer they describe. A measurement computed over a buffer that contains half a cycle will report something, and it will be wrong. Check that your capture covers at least a few complete cycles before trusting a period, frequency or duty-cycle reading.

Cursors

There are four draggable cursors: two vertical and two horizontal.

Cursor pair	Reads
Vertical (2)	Time positions and the interval between them
Horizontal (2)	Voltage levels and the difference between them

Drag a cursor to place it. The readout shows each cursor’s absolute position and the delta between the pair, which is usually the number you actually want — the width of a pulse, the height of a step, the interval between two edges.

Cursors are the tool to reach for when:

The feature you care about is one specific part of the waveform, not the whole buffer — automatic measurements describe the whole capture.
You want to measure something the automatic set does not compute.
You want to verify an automatic measurement by hand, which is a reasonable thing to do on an uncalibrated instrument.

A note on accuracy

Voltage readings pass through your probe, the programmable gain stage and one of two converters, none of which is calibrated against a traceable reference out of the box — and the instrument cannot tell whether a 1× or 10× probe is attached, so it cannot correct for it. Treat absolute voltage readings as nominal.

Relative measurements — the ratio between two levels, the interval between two edges, whether a signal is symmetric — are considerably more trustworthy than absolute ones, because the error terms largely cancel.

The repository includes a separate calibration tool that characterises the analog chain against an external oscilloscope and fits a model the app can use to pre-compensate requests. That is a bench procedure, not something the instrument does for itself.