I think perhaps reversing the phase (when negative) and adding/subtracting it from the original (equivalent of rail) might create a class-B type distortion perhaps?
Documented my experiments with a grc flowgraph and video..
Thoughts?
2 grc files are hierarchical blocks and one is the actual flowgraph
On Wed, Jan 26, 2022 at 2:31 AM Anish Mangal <anishmg@umich.edu> wrote:
Hi. Yes. I am just looking at modeling a class-B distortion at the moment, but could someone guide on how to convert between quadrature signals and real signals. Because the rail (or the other one I was trying .. abs, only work on real signals)The simple example im trying to shoot for is create a wbfm waveform, "clip/distort" it, and demodulate it and see the noise in the spectrum.Thanks for the replies!! :)On Wed, Jan 26, 2022 at 1:55 AM Nick Foster <bistromath@gmail.com> wrote:Anish,If you really just want to model crossover distortion in a class-B amplifier, you could use a pair of Rail blocks:If you're trying to model the distortion created by a real solid-state amplifier, and not trying to correct it with predistortion, there are a million different models which attempt to accurately characterize distortion in SSPAs: Rapp, Saleh, and Ghorbani seem to be most widely used. They're all pretty simple.Here's a very simple, memoryless model (Ghorbani) implemented as an embedded Python block:Some basic information about the model can be found here:NickOn Tue, Jan 25, 2022 at 12:03 PM Wheberth Damascena Dias <wheberth@gmail.com> wrote:Hello Anish,Non-linear power amplifier modeling and pre-distortion is a vast subject.If you want to go deep in this matter I would suggest you to take a look at Baseband polinomial models.Here a reference I have used some time ago:If you just need something quick, you may want to lookout for AM/PM models, such as the Saleh model.Good luck!Best RegardsWheberth DiasOn Tue, Jan 25, 2022, 20:44 Anish Mangal <anishmg@umich.edu> wrote:Hi,How should I go about modeling the distortion introduced by a class-B amplifier stage that clips the signal when its value is below zero?Example:I want to combine two FM modulated signals, pass them through this "class-B distorter", demodulate them, and analyze the quality of the signal produced (compared with the undistorted one).How should I go about doing it.Created the flowgraph attached, but this is obviously wrong. :)--Anish
--Anish
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Anish
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