Hi Kelly,


I assume your dBc is with respect to the RF signal. In that case -36 dBc should be ok since it means you can achieve an SNR of 36 dB. However, as you say, it depends on whether you can actually get that kind of DCD.

Just one last check which I guess you are doing correctly anyway, but you are checking your IF differentially right? Another thing, I believe you will get better cancellation using a quadrature design.


regards,
Aaron

Hi kelly,

   As you mentioned , you IP3 curves seem a little weird below 0 dBm.I have encoutered the same problem before, I think maybe two reasons causeing this situation. At first, it is possible that you mixer's noise performance is too bad , so in the low level of input power , the desired sigal is easily distoried by nois;For another reason  ,you simulation is not accurate,you needn't use QPSS , it seems take too long time to run one time,just take harmonic balance (hb)with two tones,just remember the harmonic numbers should be large enough to ensure your simulation accuracy.