prsctrl.data.functions.dI

dI(lR, slR, theta, stheta, dI_offset, sdI_offset)

Calculate the total (R) signal component.

delta I = sqrt((delta I_X)^2 + (delta I_Y)^2) * (-1) if |theta| >= 90

The lock-in R offset is only subtracted from delta I_X, since it is assumed to be in-phase. The sign is flipped when |theta| >= 90, since that is assumed to be not a 180° phase shift, but a negative signal. This assumption is valid if the phase never “creeps” towards 90°, but is always either near 0° or near 180°. If the phase is near 90°, it is not possible to decipher whether this is a phase shift or a sign flip!

Parameters:

• lR – R from lock-in

• slR – standard error of R from lock-in

• theta – offset-corrected theta from lock-in

• stheta – standard error of offset-corrected theta from lock-in

• dI_offset – R-offset from lock-in

• sdI_offset – standard error of R-offset from lock-in

Returns:

delta I