The supply current was sampled 1024 times over a very short time interval. The data so obtained is given in column B of the accompanying Excel worksheet1. This worksheet has been set up to give a graph showing the spectral components of the data. Question 3 i) Obtain the Fourier Transform for the data using the Fourier Analysis tool of Excel. The transformed data should commence in cell D2. ii) Identify the principal frequencies in the current waveform. iii) Estimate the total harmonic distortion [THD] present in the current waveform using the formula: n max THD(I)=1/I1 SQRT Σ (In)^2 x 100% n=2 where I1 is the r.m.s. value of the fundamental current, In the r.m.s value of the nth harmonic and n(max) is the number of the highest measurable or significant harmonic. [Note the vertical axis of the spectrum graph is scaled in (current)2.] iv) Attempt to synthesise the shape of the original waveform from its principal harmonics [e.g. sketch the waveforms of the harmonics on the same time axis and add them together]. I am struggling with 3iii. for I1 rms I have SQRT 15.8 + 8.77 + 6.25 = 5.55A n max I have 15.8 as its the highest magnitude. But I'm not sure what to do to find In? any help would be appreciated.