"Dirt" comes from a variety of sources.
power supply
overdrive
bias
VSWR mismatch
linearity
Basically there are two areas other than power supply (under/over volt, poor regulation) that create crud.
IMD is in band, near transmitted frequency.
or
Harmonic energy at multiples of frequency.
First deal with harmonic energy.
Unfortunately any discussion about IMD (inter-modulation distortion) leads back to linearity first then falls rapidly into an esoteric black hole of advanced mathematics or endless cut, fit, try, (it's the English way...).
What I'm suggesting is that application and design go hand in hand with device characteristics. I can go deeper into this but if you want to go ahead on your own , compare input-output graphs for popular transistors. What you're looking for is a nearly straight line. There will be some surprises. Hint, I really like the 2SC2290.
Some non-linearity can be straightened out with negative feedback networks. Lately a process "pre-distortion" inputs non-linear gain to the input in order to create a linear transfer function.
power supply
overdrive
bias
VSWR mismatch
linearity
Basically there are two areas other than power supply (under/over volt, poor regulation) that create crud.
IMD is in band, near transmitted frequency.
or
Harmonic energy at multiples of frequency.
First deal with harmonic energy.
Unfortunately any discussion about IMD (inter-modulation distortion) leads back to linearity first then falls rapidly into an esoteric black hole of advanced mathematics or endless cut, fit, try, (it's the English way...).
What I'm suggesting is that application and design go hand in hand with device characteristics. I can go deeper into this but if you want to go ahead on your own , compare input-output graphs for popular transistors. What you're looking for is a nearly straight line. There will be some surprises. Hint, I really like the 2SC2290.
Some non-linearity can be straightened out with negative feedback networks. Lately a process "pre-distortion" inputs non-linear gain to the input in order to create a linear transfer function.