Which parameters should be simulated in a VCO?

[icx]

How to simulate a vco?

When design a vco ,
which parameters should be simulated?and how to do that?
thanks.

 

[mpig09]

Re: How to simulate a vco?

Dear icx :

VCO needs these parameters :
1. VCO gain
2. control voltage =0V, VCO output frequency

you can sweep DC for control voltage to plot this curve, then calcuate the
parameter.


If you have any question, please that me know.

mpig09

 

[Miguel Gaspar]

How to simulate a vco?

Equation of the VCO is:
f= fo + k Vc

fo free running frequency
k sensitivity usually Hz/V
Vc Control Voltage

When there isn't Vc (Vc=0), then the output of the VCO is fo.
if you need a frequency variation of 120kHz for a variation of 3 volts, then you need a k = 40kHz/v.

 

[yaxazaa]

Re: How to simulate a vco?

vco characteristic: frequency vs control voltage
vco immunity of vdd/vss

 

[flushrat]

Re: How to simulate a vco?

and phase noise and total jitter
eg:
dbc@100kHz dbc@1MHz

 

[maddy]

How to simulate a vco?

Freq Range, PhaseNoise, Sensitivity, Supply Pushing, Load Pulling, Output power etc are some important specs. If you are using Cadence suite, cdsdoc has info on testbenches for simulating oscillator

 

[icx]

Re: How to simulate a vco?

Thanks all!

“dbc(at)100kHz dbc(at)1MHz ”
what does this mean?

Added after 3 minutes:

Freq Range, PhaseNoise, Sensitivity, Supply Pushing, Load Pulling, Output power etc are some important specs. If you are using Cadence suite, cdsdoc has info on testbenches for simulating oscillator

What's the “Supply Pushing?”
thanks.

 

[holddreams]

Re: How to simulate a vco?

vco characteristic: frequency vs control voltage
vco immunity of vdd/vss

what does “vco immunity of vdd/vss” mean?how can we check this in the circuit? I mean ,how to simulate this ?
thanks.

 

[maddy]

Re: How to simulate a vco?

sweep your supply voltage by +/- 10% and with all other parameters fixed and see how the output frequency varies. The slope of the plot of the freq vs supply voltage gives Supply pushing

Maddy