Optimal grouped B-spline windows for power spectral density estimation

The solution, of minimizing the effect known as spectral leakage into the sidelobe of a window function is to obtain a continuous waveform, which results in lesser sidelobe level. Conventional windows are able to control these characteristics by only one parameter. To suppress the spectral leakage, a window function in the time domain is used to shape the finite time sampled measurement data. The higher order of continuity of the of the time window function can be obtained by using grouped B-spline functions with three control parameters for power spectral density estimation.