# Deriving Data and Plotting

In the following x means multiply.

Let

z1=2 x pi x 650 x 10^6
p1=2 x pi x 1.9 x 10^9
p2=2 x pi x 5 x 10^9
deltaF=.2 x 10^9


In the following j is the imaginary representation Now let N=(adc x p1 x p2)/z1 and

M=(-2 x j x pi x freq x z1)/((-2 x j x pi x freq+p1) x (-2 x j x pi x freq+p2))


The base formula is abs(20 x log(N x M,10)) or the absolute value of 20 log(N x M) where the log base is base 10. Within the base formula is freq (the value of the frequency) which will be swept from 10^8 to 10^11 in steps of deltaF (.2 x 10^9)

The vertical range is from -25 to 5 (linear scale) and the horizontal range is from 10^8 to 10^11 (log scale)

The horizontal axis as stated is a Log scale as opposed to Linear.

How do I set this up in Sage to plot per the above? Thanks.

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I'm not getting the vertical range that you are specifying, but here is what I've got. Note that the log plot only works in the latest release (5.2) of Sage.

z1=2 * pi * 650 * 10^6
p1=2 * pi * 1.9 * 10^9
p2=2 * pi * 5 * 10^9
deltaF=.2 * 10^9

M(freq)=(-2 * i * pi * freq * z1)/((-2 * i * pi * freq+p1) * (-2 * i * pi * freq+p2))

g(frq)=20*abs(log(N*M(frq),10))

pts=[(frq,g(frq).n()) for frq in srange(10^8,10^11,deltaF)]

list_plot(pts, scale='semilogx')

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Thanks for the answer. I actually needed to have the absolute value of N x M(freq) and that should give me the right range.

What is the correct syntax? I have tried log(abs(N x M(freq)),10)) and that does not seem to work and I get an error.

Also, is there a reason for the change from freq to frq? Thanks!

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It's okay, I got it to work with the abs defined where I wanted it and had one minor change to the equation to get the correct range. Now I need to find out how to get Sage 5.2.

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