Chart Cursors

Cursors are how you read numbers off a chart. In Deepsona a cursor is an object: you can place several of the same type on one chart, each one has its own right-click menu, its own appearance and its own set of calculations, and all readings are collected in a table on the plot and in the floating Cursor Legend. Cursors are part of the page — they are duplicated with the page, exported with the image, and carried into an Active Picture.

Cursor Types

Menu entry	What it does
Add Single Cursor	One line. Reads the value of every curve where it crosses.
Add Double Cursor	Two lines defining a band. Gives interval statistics between them.
Add Harmonic Cursor	A comb at `n · f₀`. Drag any line to set `f₀`; reads every harmonic and THD.
Add Sideband Cursor	Sidebands at `f_c ± k · spacing`. Drag the centre to move it, drag a sideband to set the spacing.
Add Automatic Cursor → Peak / Valley	Labels the most prominent peaks (or valleys) automatically, with adjustable parameters.
Add Coupled Cursor	One cursor dropped on every chart in the Data Viewer that shares the chosen X unit; they all move together.
Add Processing Cursor	Colormaps only — cuts a section out of the map. See Processing Cursor.

Adding a Cursor

Right-click on an empty area of the chart (not on a cursor line and not on an axis).
Open one of the Add … Cursor entries.
Choose the direction from the submenu (see the next section).
Drag the cursor into position, or use the cursor's own menu to jump to a sample, a local extremum or the global maximum.

Remove all Cursors in the same menu clears every cursor on the chart at once.

Direction: X, Y and Cross

Single, double and harmonic cursors can act along four directions. The submenu adapts to the chart type:

Chart type	Submenu entries	Meaning
Curve plot	X	Vertical line, reads along the horizontal axis.
	Y (Front)	Horizontal line on the left-hand Y axis.
	Y (Back)	Horizontal line on the right-hand Y axis (only when a second Y axis is in use).
	Cross Y (Front)	Crosshair tied to the left-hand Y axis.
	Cross Y (Back)	Crosshair tied to the right-hand Y axis.
Colormap	X	Vertical line along the horizontal axis.
	Z	Horizontal line along the vertical axis.
	Cross	Crosshair on the map.

Front and Back are the left and right Y axes of a curve plot. A cursor belongs to the axis you picked, so on a chart with two different quantities (for example level on the left and RPM on the right) each cursor reads the axis it was created for. A colormap has no front/back pair — its vertical axis is Z and the colour scale carries the Y quantity, which is why the colormap submenu offers X, Z and Cross instead.

Sideband cursors are offered on the X direction only. A crosshair cursor moves as one piece: drag the intersection and both lines travel together, with the X and Y coordinates shown at the crossing point.

The Cursor Menu

Right-click on a cursor line to open that cursor's own menu:

Entry	Effect
Zoom	Double cursors only — zoom the chart to the band between the two lines.
Remove / Remove All	Delete this cursor, or every cursor on the chart.
Move to...	Type an exact coordinate for the cursor.
Move to Next / Previous Sample	Step one data point at a time.
Move to Next / Previous Local Maximum	Jump peak to peak.
Move to Next / Previous Local Minimum	Jump valley to valley.
Move to Global Maximum / Minimum	Jump to the extreme value of the curve.
Snap to data values	Keep the cursor on measured samples instead of anywhere in between.
Lock Position	Freeze the cursor so it cannot be dragged by accident.
Calculations ▸	The tick list described below.
Automatic Peak/Valley parameters...	Automatic cursors only — opens the parameter dialog.
Properties...	Appearance and behaviour of this cursor.

Cursor Calculations

Every entry in Calculations is a tick box; ticking one adds a column to the cursor's readout table. Which entries are offered depends on the cursor type and on the data.

Double cursor — statistics over the band

Entry	Result
Axis Range	The span covered by the two lines.
RMS	Root-mean-square of each curve inside the band (curve plots).
Min / Max	Smallest / largest value in the band, together with the position where it occurs.
Average	Mean value in the band.
Range	Max − Min.
Freq (1/Δt)	Reciprocal of the cursor spacing — the repetition frequency of the interval you bracketed.
Linear Regression ( a; b; R² )	Least-squares straight line through the band and its coefficient of determination (curve plots).

Single cursor — damping from the resonance peak

Place a single cursor near a resonance peak of a frequency-response type curve. The half-power (−3 dB) bandwidth around that peak gives:

Q = f₀ / (f₂ − f₁) · ζ = 1 / (2Q) · η = 2ζ = 1 / Q

Entry	Quantity
Q (/)	Quality factor.
ζ (%)	Damping ratio, in percent of critical damping.
η (/)	Loss factor.

The half-power points are taken 3 dB below the peak on a dB axis, or at peak / √2 on a linear amplitude axis, and the crossings are interpolated between samples.

Single cursor on a spectrum — tonal metrics

On an equally spaced sound-pressure spectrum a single cursor additionally offers:

Entry	Result
Prominence Ratio	PR of the tone at the cursor frequency.
PR Prominent	Whether that tone counts as prominent by the PR criterion.
Tone-to-noise Ratio	TNR of the tone at the cursor frequency.
TTNR Prominent	Whether that tone counts as prominent by the TNR criterion.
ΔL - Tonality DIN45681	Tonal audibility of the tone according to DIN 45681.

Harmonic cursor

Entry	Result
THD	Total harmonic distortion computed from the comb lines, expressed in percent. It is ticked by default when a harmonic cursor is created.

Entries that make no sense for the current chart are not offered. RMS and Linear Regression are curve calculations and do not appear on a colormap; Q / ζ / η require a single line cursor on a curve; the tonal metrics require a spectrum with equally spaced lines.

Cursor Legend and the Readout Table

Readings are presented as a table on the plot: one row per curve, one column per cursor position, plus one column for each ticked calculation and one for the X unit. Single and crosshair cursors show their table straight away; for a double cursor the calculation columns are off until you tick them. The table can be dragged to a free spot on the plot, and it travels into an exported image or an Active Picture.

The Cursor Legend submenu in the chart's right-click menu controls the floating legend panel that gathers all readings in one place:

Entry	Effect
Auto	Show the legend for whichever cursor directions are present.
X	Show readings of X cursors.
Y (Front) / Y (Back)	Curve plots: readings of the left / right Y axis cursors.
Cross Y (Front)	Curve plots: readings of crosshair cursors.
Z / Cross	Colormaps: the corresponding directions on the map.
Copy Legend Values	Copy the whole legend content to the clipboard for pasting into a spreadsheet or report.

Coupled Cursors

A coupled cursor puts one cursor on every chart of the Data Viewer that uses the same X unit, and keeps them synchronised: drag one and all the others follow.

Right-click a chart and open Add Coupled Cursor. The submenu lists the X units that actually occur on the current page (Hz, s, rpm, order …).
Pick a unit. One cursor appears on each matching chart.
Drag any of them — the whole set moves to the same coordinate.

This is the fast way to compare the same frequency across several channels, or the same moment in time across a level trace, a spectrum map and an order chart.

Automatic Peak and Valley Cursors

Add Automatic Cursor → Peak or Valley labels the most prominent extrema for you. Open Automatic Peak/Valley parameters... (from the same submenu, or from the cursor's own menu) to tune the detection:

Parameter	Options / default	Description
Source data	First curve (default), All curves, Selected curve	Which curves are searched.
Maximum number of extrema	8	Upper limit on how many peaks or valleys are labelled.
Amplitude threshold (dB)	20	Measured downwards from the highest value for peaks, upwards from the lowest value for valleys. Extrema outside that window are ignored.
Gate (% of dB range)	1.0	Minimum amplitude change after a direction reversal for it to count as an extremum. Raise it to suppress ripple on noisy curves.

Cursor Properties

Properties... in a cursor's own menu opens its appearance and behaviour settings:

Setting	Description
Label	Text shown for this cursor in the readouts.
Line style	Solid, Dash, Dot or DashDot.
Color	Line colour. Each cursor type starts from its own default colour.
Line width (px)	Thickness of the cursor line.
Decimals	Number of decimal places in this cursor's readings.
Number of lines	Comb cursors only — how many harmonic or sideband lines to draw.
Show value on the cursor line	Print the coordinate next to the line itself.
Snap to data values	Same as the menu tick: restrict the cursor to measured samples.
Lock Position	Same as the menu tick: freeze the cursor.

Labels and Other Chart Commands

Besides cursors, the chart's right-click menu carries the commands you need while reading a plot:

Command	Shortcut	Effect
Label Cursor	Ctrl+Left for a single label	Left-click a curve to annotate that point with its value; Esc or right-click leaves the mode. Labels can be dragged.
Undo Last Label / Clear All Labels	—	Remove the newest label, or all of them.
Select All Curves / Deselect	Ctrl+A	Selection is shown by a thicker line.
Delete Selected Curves	Del	Remove the selected curves from the display.
Copy Values ▸ All / Between X limits	—	Copy the plotted numbers to the clipboard. On a colormap the whole matrix is copied.
Copy Chart as Image	—	Copy just this chart as a picture.
Display Size ▸ Maximize / Restore	—	Fill the Data Viewer with this chart, then restore the grid.
Reset Axes	Home	Return the axes to their initial view.
Undo Axis Setting	Backspace	Step back through the recent axis changes one at a time.
Set Axis Range...	double-click an axis	Enter the range numerically.
Color Palette ▸ Black-Red / Deepsona	—	Colormaps only — switch the colour scheme.

Troubleshooting

I keep selecting the curve instead of grabbing the cursor

Aim at the cursor line itself; the grab zone is a few pixels wide on either side. Once you have it, Lock Position prevents further accidental drags — unlock when you need to move it.

A calculation is missing from the Calculations submenu

The list adapts to the cursor and the data. Interval statistics need a double cursor; Q, ζ and η need a single line cursor on a curve plot; PR, TNR and DIN 45681 need a single cursor on an equally spaced spectrum; THD needs a harmonic cursor. RMS and Linear Regression are not offered on colormaps.

My cursor reads the wrong axis

On a chart with two Y axes, a cursor belongs to the axis it was created for. Remove it and add it again as Y (Front) or Y (Back) as appropriate.

Q or ζ shows nothing

The half-power points must exist on both sides of the peak inside the plotted range. Widen the axis range, or move the cursor closer to a clearly resolved resonance peak.

The automatic cursor labels ripple instead of real peaks

Raise Gate (% of dB range), or lower Maximum number of extrema, in Automatic Peak/Valley parameters....

Remove all Cursors clears the whole chart without asking. If the readings still matter, use Copy Legend Values or Copy Values first.