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PAC and PXF simulation Result inconsistence in terms of IRR

Hubertastra

Good day,

I'm using virtuoso 6.1.6 and I'm trying to simulate IRR of a receiver front-end. The IQ separation is generated by a RF hybrid coupler(transmission-line based, using mtline component in analoglib) and IQ recombining is realized at baseband (BB) using another BB hybrid coupler (ideal S-parameter defined n-port). I think I'm clear with the difference between PAC and PXF. I got different result using PAC and PXF as following:

Let's assume LO frequency is 15GHz, both IQ channels are driven by the same LO.

(1) PAC: a. set "PAC magnitude=1" at input RF source and PAC simulation frequency at 15G~16G, looking at final combined output (BB) at -1harmonic sideband (0~1GHz), the gain is A1.

               b. set "PAC magnitude=1" at input RF source and PAC simulation frequency at 14G~15G, looking at final combined output (BB) at -1harmonic sideband (1GHz~0), the gain is A2.

      IRR= A1-A2, this result shows around 40dB IRR.

(2)PXF: Set PXF node at final combined output (BB) and PXF simulation frequency at 0~1GHz, looking at "1" and "-1" sideband PXF transfer function of input source.  Their difference is the IRR, but the simulation result only shows <1dB IRR.

When I used S-parameter defined n-port as RF hybrid coupler as well, this inconsistence disappeared so I wondered if this is caused by the transmission line. BTW, Harmonic Balance is chosen for PSS engine as I found shooting engine doesn't work with transmission line. If I'm wrong about this, please point out.

I'm not sure whether I descript my question well, if you have anything that want we to clarify, please feel free.

 

Thank you,

Yang

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  • Hi Yang,

    I suggest you contact customer support - if I've understood your description properly, then I would expect the results to be very similar using either approach. I'd also suggest you use something more recent (you didn't say which Spectre version you're using, but IC6.1.6 as an IC version is two major releases ago and the last updated (hot fix) version was 5 years ago and it was initially released nearly 7.5 years ago, so I'm guessing your spectre is a similar vintage.

    Regards,

    Andrew.

Reply

  • Hi Yang,

    I suggest you contact customer support - if I've understood your description properly, then I would expect the results to be very similar using either approach. I'd also suggest you use something more recent (you didn't say which Spectre version you're using, but IC6.1.6 as an IC version is two major releases ago and the last updated (hot fix) version was 5 years ago and it was initially released nearly 7.5 years ago, so I'm guessing your spectre is a similar vintage.

    Regards,

    Andrew.

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