impulse sensitivity function

Dear all,

Could anyone introduce some tutorial or step-by-step simulation of the ISF method? I want to use this to simulate the QVCO. I have seen some of the paper talking about this. However, I do not know very well how could I simulate it. Could anyone give me some materials about this?

Thanks

wccheng

You need to do a lot of transient simulations to simulate the ISF. Do the transient and get the undisturbed waveform. Then do the transient and introduce an impulse after a short duration using a piece wise linear source and get the phase change in the waveform as compared to the original. Do this for a number of places in 1 time period to get the desired resolution. This will give you the ISF, and since its periodic simply repeat it. Right now the simulation tools don't have the facility to simulate it directly.

Dear Sir,

Do you have any tutorial notes to teach the simluation procedure method? It is because I want to simulate it.

thanks

wccheng

The steps are exactly like I mentioned. You have to do the transient simulations. I think they can be done easily. And just measure the phase changes that occur due to the different times you put the impulse.

Hi to all
I want to calculated the isf.
do I must remove noise source in circuit and replace by impulse or I must apply impulse in circuit with noiseless noise source.

hi,
i didnt understand the procedure.how can i give impulse source in the circuit?is it possible in hspice?or any other software where simulation can be done to measure ISF.please kindly help me.

Hi lisamoni,
Like I suggested above. You can create a near impulse using a pwl source.

hi aryajur
i am really sorry that i m not still clear.how can i give PWL source in hspice netlist?can u please kindly tell me the syntax?i cant get it

Hi lisamoni,
Here is a link where you can find the Hspice manual.
Avant! Star-Hspice Manual

you can specify an impulse using a pwl source like this:

vimp node1 node2 pwl(0 0 100u 0 100.001u 3 100.002u 0)

this gives a triangular impulse which is 2ns wide at 100us across node1 and node2.

thank u very much aryajur,i will try it