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Design >> RF Design >> input impedance of LC-VCO
https://designers-guide.org/forum/YaBB.pl?num=1451502371

Message started by AZADBAKHT on Dec 30^th, 2015, 11:06am

Title: input impedance of LC-VCO
Post by AZADBAKHT on Dec 30^th, 2015, 11:06am

hi all
i want to simulate the input impedance of an LC-VCO in cadence-virtuoso
can anyone help me?

regards,
Azadbakht

Title: Re: input impedance of LC-VCO
Post by Ken Kundert on Dec 30^th, 2015, 11:04pm

Impedance is voltage over current. You can measure it with a small signal analysis such as PAC, though a simple AC analysis might be accurate enough.

-Ken

Title: Re: input impedance of LC-VCO
Post by AZADBAKHT on Dec 31^st, 2015, 9:28am

thank you very much sir Ken Kundert

in reality, i need to calculate impedance of control voltage line!
can you help me in detail for do this analysis (how to setup port and detail properties of them!)?

regards,
Azadbakht

Title: Re: input impedance of LC-VCO
Post by Ken Kundert on Jan 1^st, 2016, 2:15pm

You drive the input with a voltage source. On the source you specify a small signal magnitude. If you specify the magnitude to be one volt and plot the current, then the current equal to the admittance.

-Ken

Title: Re: input impedance of LC-VCO
Post by AZADBAKHT on Jan 2^nd, 2016, 12:06am

thank you so much dear Ken Kundert