Ask Your Question

Deriving Data and Plotting

asked 2012-08-14 16:15:56 +0100

gjm gravatar image

updated 2012-08-14 21:08:26 +0100

calc314 gravatar image

In the following x means multiply.


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.

edit retag flag offensive close merge delete

3 Answers

Sort by ยป oldest newest most voted

answered 2012-08-14 22:50:51 +0100

calc314 gravatar image

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

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


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

list_plot(pts, scale='semilogx')
edit flag offensive delete link more

answered 2012-08-15 15:34:28 +0100

gjm gravatar image

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.

edit flag offensive delete link more

answered 2012-08-15 15:18:15 +0100

gjm gravatar image

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!

edit flag offensive delete link more

Your Answer

Please start posting anonymously - your entry will be published after you log in or create a new account.

Add Answer

Question Tools


Asked: 2012-08-14 16:15:56 +0100

Seen: 354 times

Last updated: Aug 15 '12