Flat Top Window

C/C++ Equivalent: NISCOPE_VAL_FLAT_TOP_WINDOW

The Flat Top window has the best amplitude accuracy of all the window functions. The increased amplitude accuracy (±0.02 dB for signals exactly between integral cycles) is at the expense of frequency selectivity. The Flat Top window is most useful in accurately measuring the amplitude of single frequency components with little nearby spectral energy in the signal. A Flat Top window is applied to the waveform using the following equation:

y[i] = waveform[i] × (0.2810639 – 0.5208972cos(w) + 0.1980399cos(2w))

where w = (2)i/n and n is the waveform size.