Hi.
Show me portion of netlist regarding analysis setting,
for example, pss, pnoise, options, port, vsin statements.
And show me output log of Spectre about input and output frequency.
Maybe you set wrong setting in pnoise.
Your conditions are:
RF : port, 50ohm, large, 1500MHz
LO : vsin, large, 1504MHz
IF : port, 50ohm, dc, 4MHz
Quote:Ouestion 1) In PSS i set the output harmonics to 10, is this reasonable, or do i have to set to 400. Would this parameter affect the noise simultion?
Fundamental Frequency is 4MHz, so harmonics of 10 is too small.
Rather set "Select from range" or "maxacfreq"
Quote:Question 2) In PNOISE, sweep type is absolute. If i change it to relative the noise figure is better. However i not really sure if it is correct.
If you set IF frequency in pnoise, you have to set sweep type as absolute.
Quote:Question 3) From the noise figure graph, i always noticed a hugh spike near the RF/LO frequency.
This is natural.
Quote:Question 4) I would be able to get reasonable noise figure, when i set the RF port type to DC, beat frequency is PSS is automatically 1.504G. Is this meaningful. Got this technique from some mixer cadence lab session online.
http://www.designers-guide.org/Forum/YaBB.pl?num=1184111670/1#1 Quote:Question 5) There would be a LNA in front of my Mixer, however my RF port is set to 50 Ohms, how could i bring the simultion setup to closer to my LNA output? I could sim the LNA output S22, which has a real and imag part, can i replace the 50 Ohm by this value?
If my memory is correct, current Spectre support "port" with reactance in HB PSS.
Although it is not restricted to you, read manual or contact with technical support of EDA vendor.