Extraplotation of impedance data

I have experimental impedance data for Magnitude(ohm) and Phase(degree) against frequency from 1 KHz to 250 kHz at interval of 500 Hz. I am able to plot bode and nyquist plot from this impedance data after loading the data in workspace from excel sheet. However, i need to plot Bode and Nyquist plot from 1 Hz to 10 MHz. In this case how to exptraplot impedance data in the range from 1 Hz to 1 KHz and from 250 KHz to 10 MHz from the nature of the existing limited impedance data?. Attached alongwith the code of loading data. Requesting help

textFileName=['C:\Users\EI3\Desktop\BIOIMPEDANCE_processed\DATA_BASE\data\mean_of mag&phase.xlsx'];
f=xlsread(textFileName,'Mag_mean','A2:A500'); %Frequency only
m=xlsread(textFileName,'Mag_mean','B2:B500'); %Magnitude only
p=xlsread(textFileName,'Phase_mean','B2:B500'); %Phase only

PHA = p; %phase of experimental result
AMP = m; %gain of experimental result
% W = f*2*pi; %transforming frequency in Hz to rad/s
Ts = 0;
zfr = AMP.*exp(1i*PHA*pi/180);
fr_data = idfrd(zfr,f,Ts);

%For Bode plot of data
    bode(fr_data);    %plot bode plot in Hz
%For Nyquist plot of data
    nyquist(fr_data);    

Answer 1

[Star Strider]

First, I doubt that extrapolating from 250 kHz to 10 MHz is appropriate in any event.

However it could be, if you identified the model as for example a state space model (use ssest), then use compare to check it, and continue refining the model as necessary. You could then use findstates with lsim and an appropriate time vector, then take the Fourier transform (fft) of the result. This would be appropriate if your model has non-zero initial conditions. If it has zero initial conditions, simply use bode (see Bode Plot of Identified Model) and specify the frequency range.