Extrapolate data after shifting plot

Hello,

In the code provided, I have shifted plot 1 in the positive x-direction, but in doing so, I have no data now from x=1 to x = 4. Also, the x-axis values go beyond 100000.

I wanted to have an end result where my x-axis values will be the same for both plots. I attempted this in excel, where I selected a few cells for the shifted y-data then did a data fill for the shifted plot. I then copied the x-axis values from plot 1 over to the shifted plot

This is a screen shot of the excel table showing the fist 10 points:

Is it possible to have the original plot and shifted plot x-axis values be the same? Thanks for your help.

v=csvread('data_extrap.csv');
freq1 = v(:,1);
plot1 = v(:,2);
shift_freq1 = freq1*4;
semilogx(freq1,plot1); 
grid on;
hold on
semilogx(shift_freq1,plot1);
legend('plot 1','shifted');
hold off

Answer 1

[Star Strider]

I don’t see what’s missing. (I don’t do any significant data processing in Excel, so I can’t comment on whatever you did in Excel.)

I would use the MATLAB interp1 function. Read the documentation on it to see how to do what you want (since I’m still not clear on that). Consider using 'linear','extrap' if you want to do extrapolation.