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How to make VCO start to oscillate in ultrasim? (Read 5881 times)
ahhfyz
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How to make VCO start to oscillate in ultrasim?
Jan 05th, 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
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Re: How to make VCO start to oscillate in ultrasim?
Reply #1 - Jan 6th, 2012, 2:06am
 
you have to use initial condition in ultrasim as well
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weber8722
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Re: How to make VCO start to oscillate in ultrasim?
Reply #2 - Jan 10th, 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
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Re: How to make VCO start to oscillate in ultrasim?
Reply #3 - Jan 12th, 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 12th, 2012, 10:39pm
 
weber8722 wrote on Jan 10th, 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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