Help with Oscillator in ADS

[skyismylimit]

how to check whether my oscillator has sufficient gain for start up in ADS?

I am working with a colpitts oscillator. I couldnt run the transient simulation as it says lots of warnings when i use the ATC components from ADS.

I used HB analysis, but the manual says it is a steady state simulation. It asks me to test with osctest component. Also, it mentions that the characteristic impedance value of the osctest component may affect the results. I am not sure of wat value to use for the Z value in the osctest component.

Is there any other way to test the start up? Or any rectification for the two methods i have tried?

Please help..

 

[khouly]

what is the transistor u use , and what is the frequency ? of operation

Khouly

 

[BigBoss]

Check the closed loop gain and phase to maintain the oscillation conditions. If they are sufficiently satisfied, the circuit may oscillate.

The best check out method to apply a small transient simulation by forcing a simple pulse over loop path.

 

[skyismylimit]

I am using a new device which is a SOI MESFET. I have a non linear model for the device. the frequency is 400MHz.

I tried transient simulation but it is giving unreasonable values of KV at the output. There are warnings about the ATC components Imapfreq when i run the transient simulation.

Is the HB analysis only for the steady state?

 

[Abhishekabs]

hi friend
I also faced same problem with ADS
The good solution while working in ADS is
Test your individual components that is apply transiant simulation to each component(say microstrip line) & observe response.
If it is expected directly go for fabrication of oscillator.
best of luck

 

[khouly]

sure HB analysis is steady state analysis . but it is very efficient in oscillator analysis and phase noise calculation

khouly