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
The best Free PLL simulation (to see frequency vs time behaviour)
Started by ●October 3, 2014
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 ●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.comYou 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 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 ●October 4, 20142014-10-04
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
