Well its a LOOP no?
The vco feeds the phse det
The phase det feeds all your filter stuff
The filter feeds back to the vco
But to anayze the loop in simulation you do usually open the loop
I will use a voltage source or current source depending on the type of phase det
That feeds the filter
Then the integrator vco
Then a resistive divider that represents the divide ratio
Mark
Reply by Ro_ny●October 3, 20142014-10-03
>On Fri, 03 Oct 2014 14:38:44 -0500, Ro_ny wrote:
>
>> That I can connect it additional components e.g. opamps, logic gates
>> etc...
>> (that's why software like ADIsimPLL isn't suitable).
>>
>> Does LTSpice have a built-in VCO component that can be added, and its
>> range can be set to any frequency for example 1.5GHz?
>>
>> Thanks to all who help.
>>
>>
>> _____________________________
>> Posted through www.DSPRelated.com
>
>You can build something using the "idtmod" function in a behavioral
>source, and one of their logic functions.
>
>I've done it, I just can't remember how!
>
>--
>
>Tim Wescott
>Wescott Design Services
>http://www.wescottdesign.com
>
I appreciate the direction (seems that such command needs to be fed into
some component to make it so) though I can’t catch how come that no free
simulator nowadays contains a basic VCO.
If the above command constitutes a combination of the VCO and phase
detector I can’t use it (for example there is usually a filter in the
middle, and perhaps additional circuitry).
LTSpice seems to be free unlimited, does the free PSpice version provide
here any advantage?
Thanks
_____________________________
Posted through www.DSPRelated.com
Reply by Tim Wescott●October 3, 20142014-10-03
On Fri, 03 Oct 2014 14:38:44 -0500, Ro_ny wrote:
> That I can connect it additional components e.g. opamps, logic gates
> etc...
> (that's why software like ADIsimPLL isn't suitable).
>
> Does LTSpice have a built-in VCO component that can be added, and its
> range can be set to any frequency for example 1.5GHz?
>
> Thanks to all who help.
>
>
> _____________________________
> Posted through www.DSPRelated.com
You can build something using the "idtmod" function in a behavioral
source, and one of their logic functions.
I've done it, I just can't remember how!
--
Tim Wescott
Wescott Design Services
http://www.wescottdesign.com
Reply by ●October 3, 20142014-10-03
On Friday, October 3, 2014 3:38:44 PM UTC-4, Ro_ny wrote:
> That I can connect it additional components e.g. opamps, logic gates etc...
>
> (that's why software like ADIsimPLL isn't suitable).
>
>
>
> Does LTSpice have a built-in VCO component that can be added, and its range
>
> can be set to any frequency for example 1.5GHz?
>
>
what you can do in PSPICE is use an integrator as a behavior model for the VCO and phase detector combination. The fact that the VCO operates in frequency
and the phase detector operated in phase results in an integration is key to understanding this. The frequency is represented by an ordinary voltage so it is easy to simulate. Search "behavioral modeling"
Mark
Reply by Ro_ny●October 3, 20142014-10-03
That I can connect it additional components e.g. opamps, logic gates etc...
(that's why software like ADIsimPLL isn't suitable).
Does LTSpice have a built-in VCO component that can be added, and its range
can be set to any frequency for example 1.5GHz?
Thanks to all who help.
_____________________________
Posted through www.DSPRelated.com