Re: How to model class-B distortion of a complex signal

[Marcus Müller]

Hi Anish,

there's been a Summer project that implemented and compensated nonlinear distortion. 
Simple amplifier models are covered.

https://summerofcode.withgoogle.com/archive/2020/projects/5862185634365440
https://github.com/gnuradio/gr-dpd

You'll want to start by reading Alekh's proposal; it was pretty nice.

The model that you illustrate in your flow graph doesn't quite mathematically work out; I 
think you'll want to look into Volterra series if you want to learn about a more general 
modelling for nonlinear elements. For a more specifically useful short introduction to 
nonlinear amplifier modelling, see the MP and GMP documentation in the github link above.

Best regards,
Marcus


On 25.01.22 20:23, Anish Mangal 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

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