How do I set a sweep in LOG

[sh64]

Hi guys,

I'm trying to sweep the frequency in LOG instead of doing it like 1Hz,100Hz..1Khz in Mathcad. I have mathcad version 11.0a

Can you guys help me with that.

Thanks
Sh64

 

[GregLocock]

i:0;9999

logsweep[i:sin(i/1000*2*pi*log(i+1))

Should get you in the vicinity of a log swept sin wave. You might be surprised by the frequency content. My Mathcad computer is broken so I can't check this.



Cheers

Greg Locock

 

[sh64]

Hi Greg,

Thanks for the input

Regards

 

[RoyElectroMech]

Howdy,

I don't know if you're still looking for a solution, or if the one provided works, and maybe I don't understand your question, but I've had to generate log spaced points to plot frequency responses, and the way I do it is as follows:

pts:=(enter how many points you want)
n:=1..pts
d1:=(enter the exponent of the minimum frequency, i.e., -2 for 0.01 Hz)
d2:=(enter the exponent for the max freq, i.e., 2 for 100 Hz)
f(sub)n:=10^[d1+(n-1)*(d2-d1)/(pts-1)]

That set of definitions will give you a range variable f of n elements equally spaced logarithmically from 10^d1 to 10^d2.

A.M.D.G.