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Simulators >> RF Simulators >> Simulating a mixer with I/Q LO with QPSS
https://designers-guide.org/forum/YaBB.pl?num=1170965379

Message started by Bill Toole on Feb 8^th, 2007, 12:09pm

Title: Simulating a mixer with I/Q LO with QPSS
Post by Bill Toole on Feb 8^th, 2007, 12:09pm

I am trying to simulated an IQ mixer driven by two ideal LO sources set to the same frequency (5.247GHz) but 90 degrees apart. I also have an RF source set to 5.25GHz. When I try this with QPSS with either shooting method or Flex Balance, I can only set one LO source as the Large signal and the other LO has to be moderate as well as the RF signal (which is the way it is suppose to work). Consequently, QPSS will generate multiple intermods between both LO sources and the RF rather than treating the LO sources as one tone. I can use one LO source and pass it through a poly phase filter tuned to the exact LO frequency to generate the 90 degree phase shift but this is only valid for that frequency. Plus I have to adjust the LO level to compensate for the losses through the poly phase phase. Although this speeds up the simulation by a factor of ten times, it is not the preferable way. Is there a way to generate an ideal IQ LO from a single source or setup QPSS so it regonizes the LO sources as one tone instead of two?

Bill

Title: Re: Simulating a mixer with I/Q LO with QPSS
Post by Ken Kundert on Feb 8^th, 2007, 12:18pm

Give them the same fundname.

Title: Re: Simulating a mixer with I/Q LO with QPSS
Post by Bill Toole on Feb 8^th, 2007, 12:27pm

Duh! That was too easy!!! Worked like a charm. Thanks.

Bill