So, what exactly is a power source (P1Tone) ?

[circuit_hunter]

Hi

I got confused about this small concept.

A voltage or a current source make sense to me. An ideal voltage source maintains a constant voltage across itself, irrespective of the load attached to it. Current, in such ideal volatge source, could be anything, depending upon the external network. A non-ideal volatge source will have some internal resistance. A very similar definition for a current source.

In RF/Microwave domain, I make frequent use of power sources. I am especially referring to P_1Tone ource found in the keysight ADS. I tired to go through the manual, but could get much out of it.

So, What exactly is a power source?

I guess, it provides a constant power irrespective of the load, but what could we say about the volatage across and current through it?

 

[FvM]

I guess, it provides a constant power irrespective of the load.

No it doesn't. It provides the specified power to a matched load, as described in the manual:

The signal level is set such that the power delivered to a conjugately matched load is equal to P

It can be replaced by a voltage source with additional source impedance. The "power source" concept is however representing the common way of defining sources in RF engineering.

 

[circuit_hunter]

Thank you, FvM for the clarification: The P1Tone injects specified power to the conjugately matched load.

The reason I am asking this question is that in low-frequency analog I used to have voltage and current sources. It was much easier to visualize current and voltage waveforms in different branches and at different nodes.

Now having to deal with with the P1Tone, I am unable to get that feeling.

I perofrm Harmonic Balance in simulator and get to see voltage/current signals. But, in the end I am clueless as to how a particluar waveform is shwon like that by the simulator.

Is there any way to be able to manually plot voltage/current signals involving a P1Tone?

For example, in the follwoing circuit how can I manually predict volatge at the base of the BJT?



And how can I replace the P1Tone with a voltage source with additional source impedance, as you said above?

Can this circuit, or , more sepcifically RF Power Amplifiers (RFPAs) could be simulated using SPICE simulator? If yes, what would be equivalent of the P1Tone, a voltage or a current source? In the first edition of Steve Cripps RFPA book, he gives some SPICE codes which use voltage source for excitation. Although, I have yet to go through them deeply, I guess I can use SPICE to plot waveforms of PA, and therefore, a manual analysis method should also exist. Sorry for digression from the heading of the thread, but I am doing this to clarify my concept of power sources and being able to fully comprehend PA waveforms.


Thanks for your time.

 

[BigBoss]

Power Sources supply "Available Power" that is the delivered power to the load when the power source is terminated by complex conjugate ( general case ) impedance.
Of course, this power will be maximum when this termination condition is satisfied.