The amplitude and phase are calculated at 1000 points over the frequency range. Unfortunately, defined names do not work with Complex Functions, so most of the calculations are performanced on the on the spreadsheet.

Note that the division of the frequency is done on a logarithmic scale, see this page for details. The complex functions used are as follows:

s = COMPLEX(0,w); this function generates the complex numbers based on the frequency w;

Num = IMSUM($B$6,IMPRODUCT($B$7,$U2),IMPRODUCT($B$8,IMPOWER($U2,2)), IMPRODUCT($B$9,IMPOWER($U2,3)),IMPRODUCT($B$10,IMPOWER($U2,4)), IMPRODUCT($B$11,IMPOWER($U2,5)));

This calculates the numerator, the denominator is calculated likewise.

Amplitude =IMABS(IMDIV(V2,W2)); and

Phase = =DEGREES(IMARGUMENT(IMDIV(V2,W2))).

The calculations are done in columns U through Y.