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What should be the oscillation time ?

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rjshmadala

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oscillator ckt

hello guys,
may be it is simple but i am confusing a lot..if we run transient analysis for an osiccalltor.if it is working properly how long it should ocsillate(ex 1u..).an ideal oscillator should oscillate infinite time .but a negative gm oscillator to work properly how long should it oscillate. i mean for how long we should run transient analysis.because for me my circuit oscillating for 20ns but if i run 1u it is not oscillating..please clarify me..
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rjshmadala
 

electronics_kumar

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Re: oscillation time

i think your circuit is having very good amount of damping which attenuating your oscillating signal...ideal oscillator should not have resitance(damping element) ..but it should be purely made up of Inductance and Capacitance
 

paulux

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Re: oscillation time

There is no definite startup time for oscillator. It depends on excitation. You can inject a small pulse into the circuit during startup to see if the oscillator could start oscillation or not. If it starts and then damps, you have to check the stability of the oscillator.
 

rjshmadala

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oscillation time

Hello paulux,

i am not looking for startup time.suppose if we run transient analysis in cadence.for how long it should oscillate to work properly
 

paulux

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Re: oscillation time

There is no definite startup time. One way you can check the stability of startup of oscillation is to inject ac signal as I said before. Then it should start oscillate if it is a oscillator. If you wait more than thousands cycles but it has not started oscillation, the oscillator may have some problem.
 

huojinsi

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Re: oscillation time

If ur oscillator period is 20us and when u simulate the circuit in 1us, the oscillator cann't stop oscillating for ideal and normal operating oscillator. A normal operating oscillator have no relation with simulating time(of course it means the ckt is after stable oscillating).I think ur oscillator circuit have some wrong. Pls check ur oscillator ckt.
 

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