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Voltage Controlled Oscillator help

Question asked by vivian on Jun 10, 2014
Latest reply on Jun 13, 2014 by aehoward

I'm trying to simulate a VCO such that it takes an input from a ramp generator with a *DC voltage of 5 - 9V*, and outputs *2 - 4 GHz*. 
I want the ramp generator *rise time to be 10 msec*. 

1) I'm not sure how to set the Kv (tuning sensitivity of the VCO Hz/Volt) such that it will provide the result. 
What I understand is:
tuning voltage range = 4V
bandwidth = 2 GHz
*Kv*=2GHz/4V = 500 MHz

2) In the simulation, if I zoom in to the Vosc_out, there are spaces at certain times, the oscillation doesn't look like its increasing as time increases...? 

3) Is it possible to get a oscillation output frequency versus tuning voltage (V_ramp) graph? How can it be done? Otherwise, how can the oscillation frequency be determined, I don't think measuring the peaks for the oscillation period is correct as the period is constantly changing across time... 

Please see attached file for figures.

Thank you very much for your help,

Edited by: Vivian on Jun 10, 2014 12:17 PM