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How to make VCO start to oscillate in ultrasim? (Read 7892 times)

ahhfyz New Member Offline Posts: 5	How to make VCO start to oscillate in ultrasim? Jan 05^th, 2012, 8:57pm Hi, everyone! I am a beginner in ultrasim. Now I try to simulate a vco in ultrasim. sim_mode is set to "a(analog)", and speed is "1", but it cannot start to oscillate. I guess it is a tolerence problem, but don't know how to further set tol. Regards! Yang
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raja.cedt Senior Fellow Offline Posts: 1516 Germany	Re: How to make VCO start to oscillate in ultrasim? Reply #1 - Jan 6^th, 2012, 2:06am you have to use initial condition in ultrasim as well
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weber8722 Community Member Offline Posts: 95	Re: How to make VCO start to oscillate in ultrasim? Reply #2 - Jan 10^th, 2012, 5:50am Hi, I would add a little vpwl or ipwl source to kick-start the oscillator. This should work independent to any simulator (hspice, spectre, ultrasim, ams-designer,...). Bye Stephan
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raja.cedt Senior Fellow Offline Posts: 1516 Germany	Re: How to make VCO start to oscillate in ultrasim? Reply #3 - Jan 12^th, 2012, 10:07am hello Stephan, i guess in altrasim you don't have pulse input i guess. Thanks, Raj.
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ahhfyz

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Re: How to make VCO start to oscillate in ultrasim?
Reply #4 - Jan 12^th, 2012, 10:39pm

weber8722 wrote on Jan 10^th, 2012, 5:50am:

Hi, I would add a little vpwl or ipwl source to kick-start the oscillator. This should work independent to any simulator (hspice, spectre, ultrasim, ams-designer,...).

Bye Stephan

Setting "initial condition" can kick-start the oscillator, but ipwl fails.

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