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Within a S-parameter simulation the ‘AC power source’ is used as the source. This ‘AC power source’ has a parameter P which controls the available AC power. The P parameter is 0 dBm by default, but changing it has no effect on the simulation results. The output level remains at +10 dBm. Not even at 0 dBm.
Why is that?
Kind regards,
Rene
S-Parameters are linear, so the power level has no influence. I suspect, a power level is not even defined / needed by the solver.
How did you measure the power? The voltage and current probes do not work with a S-Paramter-Block active
The following schematic shows P=0 dBm but the measured level in the diagram is 10 dBm.
So why is it always at +10 dBm?
According to F1 help:
dBm(x,Z)
convert voltage across impedance Z into (active) power in dBm (parameter Z is optional, default 50)dBm() should be applied to voltages. S-parameters are dimensionless voltage ratios.
S21 is 1 for such a circuit. An impedance of 50 Ohm and 1 V_peak would dissipate 1/100 W of power. Equals +10dBm
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