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Design >> RF Design >> Behavioral modeling of RF transmitter
https://designers-guide.org/forum/YaBB.pl?num=1161540109

Message started by chase.ng on Oct 22^nd, 2006, 11:01am

Title: Behavioral modeling of RF transmitter
Post by chase.ng on Oct 22^nd, 2006, 11:01am

Hi all,

I am interest in finding the ACPR performance of a transmitter, previously I am relying on envelope simulation which becomes harder and harder to converge as the circuit grow larger. I read the documents written by Ken at http://www.designers-guide.org/Analysis/rf-sim.pdf, where he mentioned modeling the large signal steady state response of the transmitter so that the simulation can ran faster. But how can I do that in verilog-A? Suppose I can get the large signal steady state response using QPSS, what is next? Any help will be much appreciated. Thanks.

chase

Title: Re: Behavioral modeling of RF transmitter
Post by Eugene on Oct 23^rd, 2006, 12:51pm

Chase,

If possible, please refer to the SpectreRF User's Guide. The User's Guide has a section called "Creating and Using Transmitter J-Models" which describes in detail how to create a large signal model of a transmitter. The thing to remember about the J-model is that it is memoryless. Thus, you should model your baseband filters separately. The J-model will capture AM/AM, AM/PM, PM/AM, and PM/PM conversions. When you extract the J-model, be sure to sweep the input signal past the amplitude you expect to see. The model is good at interpolation but not extrapolation.