I can't find out any Design Issue in your questions. Your questions are simple measurement issue of RF block.
I can't understand what you are confusing.
Your "Switching PA???" is no more than TX-UpMixer or AM-Modulator which have two inputs, LO and BB.
So there is no problem in treating your case by two-tones(LO, BB) or one-tone(LO) steady state analysis.
I don't think your circuit is Switching PA.
http://www.designers-guide.org/Forum/YaBB.pl?num=1214811603AnalogAroma wrote on Apr 23rd, 2009, 5:50pm:Typical simulation techiniques in SpectreRF are suitable for a PA succeeding a mixer where RF input is coming from the mixer.
But, in my case, LO osc input does not have any baseband envelope.
And the low freq baseband input cannot use RF port symbol !!!
What do you mean ?
AnalogAroma wrote on Apr 23rd, 2009, 5:50pm:So, typical way of calculating 1dB compression point is not suitable.
How do you define 1dB compression point ?
"LO_Input_Level v.s. Output_Level with BB_Input=Constant Level(DC or Sine)"
or
"BB_Input_Level v.s. Output_Level with LO_Input=Constant Level(Sine)" ?
How do you define output power for modulation output ?
"Averaged Power" or "PEP(Peak Envelope Power)" ?
Usually I simulate simply non-modulation case where BB is DC.
Here I use swept BB of DC source with one-tone(LO) steady state analysis.
If I use sinusoidal signal for BB, I invoke two-tones(LO, BB) steady state analysis.
Here you have to choose which output power you should evaluate. "Averaged Power" or "PEP(Peak Envelope Power)".
This selection is dependent on your needs or interests.
Attached figure is Instantaneous Envelope Power of ASK signal.
http://www.designers-guide.org/Forum/YaBB.pl?num=1209812189AnalogAroma wrote on Apr 23rd, 2009, 5:50pm:Is there any way to overcome this problem in SpectreRF ?
Is there any problem in treating your case by Cadence Spectre ?, although I don't use Cadence Spectre.