SRS Labs SR850 manual Line Fit, Exp. Fit, Gauss. Fit

Math Menu

re-entered, the View Parameters function will re-display the best fit curve and the parameter window.

Both the Do Fit and View Parameters functions result in a display screen like the one shown below.

Full Scale = 100 mV	100 mS	Syncro
Dyn Reserve = 23 dB	12 dB/oct	Line	2xLin	AC	A	Do Fit:

Y		7.000 S	36.100 e-3
			Type of Fit
			Line	Exp
			Gauss
y = a + b•(t-t0)			View
t0 = 9.600000e+001 s
			Params:
a = -2.875882e-003
b = 1.136381e-003
			Limits
			Left:
			Right:
	10 S /div		0.000 S
center = 0.0	±	50.00 e-3	V
			Return:

Press Any Key To Continue...

In this example screen, the fit is a line. The curve fit region is delimited by the two limit markers (heavy dashed vertical lines) as described below. The final curve fit is plotted between the limit markers along with the data. The parameters of the fit are displayed in the window at the center.

Each type of fit has a different parameter display. The horizontal coordi- nate is t (cursor readout in time, i.e. increasing to the right) and the verti- cal coordinate is the trace value (in the units of the display).

Line Fit:	y = a + b•(t - t0)
	t0 = horizontal offset in time
	a = vertical offset in trace units
	b = slope in trace units/second
Exp. Fit:	y = ae -(t - t0)/b + c
	t0 = horizontal offset in time
	a = amplitude in trace units
	b = time constant in time
	c = vertical offset in trace units
Gauss. Fit:	y = ae -1/2(Δt/b)2+ c where Δt = t - t
	0
	t0 = peak center position in time
	a = amplitude in trace units
	b = line width in time
	c = vertical offset in trace units

5-36