[Amps] Low pass filters and saturated operation

[RCM]

> On Jan 1, 2018, at 09:39, Manfred Mornhinweg <manfred at ludens.cl> wrote:
> 
> Hi all,
> 
> after my rather pointless post moments ago about the ICAS-CCS debate, here is a somewhat more meaty year-starter for those of you who do enjoy hands-on amplifier building.
> 
> I'm currently developing an SDR that uses an MRF1K50N in the final stage. My intention is to run this in Envelope Tracking mode (ET), with a linear class AB driver stage and running the final stage in saturated class-AB. I intend to use a bank of relay-switched series-input low-pass filters, because such filters offer a high impedance to harmonics. The LDMOSFET, running in saturation, behaves closely like a voltage source, producing a voltage waveform approaching a square wave, while the series-input low-pass filter takes a roughly sine-shaped current. So this could be considered a form of class-F operation.
> 


https://www.youtube.com/watch?v=Ac7G7xOG2Ag