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# Generating a random signal in Virtuoso

Last post Mon, Dec 17 2012 3:25 AM by Andrew Beckett. 1 replies.
 Started by Donatello 06 Dec 2012 02:02 PM. Topic has 1 replies and 594 views
• #### Thu, Dec 6 2012 2:02 PM

• Donatello
• Joined on Thu, Dec 6 2012
• Posts 14
• Points 175
Generating a random signal in Virtuoso
 Hello Everyone,I am designing a circuit which needs to take a random signal and then work on it. For now, i need to know how to generate a signal, that looks like the picture on this link:http://hyperphysics.phy-astr.gsu.edu/hbase/biology/actpot.htmlI have tried using vpulse, but it only gives me options to manage voltage 1 and voltage 2. How can i change the rise and fall times of voltage 1 and 2, and perhaps the damping factor, to make it look like the above mentioned image of an action potential?I have tried using vpwl, but to no avail.  Your help would be appreciated. Thanks.
• Post Points: 20
• #### Mon, Dec 17 2012 3:25 AM

Re: Generating a random signal in Virtuoso
 You might be able to roughly model the first peak with a pulse source using the edgetype set to halfsine, but it wouldn't be terribly accurate. Better would be to do some sort of curve fit, and then either use a polynomial controlled voltage source (pvcvs) with the appropriate coefficients, or write a Verilog-A model to describe the curve as a function of time. The link you gave just gave pictures, but hopefully you have some more concrete data from somewhere.You could also use vpwl if you had a source file with sufficient data in it. Regards,Andrew.
• Post Points: 5