The Least Squares instance of the SI Estimate Impulse Response VI implements the least squares method to obtain the value of h(k).

If both the input signal u(k) and output signal y(k) of a system are available, you can obtain the value of the impulse response h(k). This method does not require a Dirac delta function as the input signal of the system. Instead, you can use a common stimulus signal and the corresponding response signal from the system to compute the impulse response mathematically. You can obtain the impulse response for both positive and negative lags.

Refer to the LabVIEW System Identification VIs Algorithm References section for more information about the least squares method.