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phase error correction

Started by Ali23 7 months ago4 replieslatest reply 5 months ago128 views

Dear All,

Thank you for your participation in my discussion in advance

I am working on the phase correction step in a receiver. The following algorithm has been already implemented:

  •  correct vectors (samples) by using the multiplication by exp (-1i * phI)
  •  compute an amplitude and rotate a vector:

A = sqrt(real^2+imag^2);

theta = arctan(imag/real);

  • now theta will be the next angle for rotation

Actually, it is the standard algorithm to correct a phase, I think.

The simulation works but it gives me a big error (for me)\" dPhi\' (difference between phases adjacent samples) under low snr

Is there an algorithm to minimize the phase difference of two vectors??



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Reply by philipoakleyMarch 18, 2021

Are you simply averaging the theta values, which have roll-over, as that roll over can cause a significant non-linearity. 

You could average the complex phase (i.e. the original complex signal divided by its amplitude) and then do the arctan step. 

There are a range of choices depending on how you handle the varying amplitude. 

Definitely worth some experimentation to see what is going on for the complex phase addition scenarios.

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Reply by Ali23March 19, 2021

i have tried...''the original complex signal divided by its amplitude''

it doesnt give me improvement

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Reply by Ali23May 25, 2021
the phase correction is done in freq domain, the timing correction is done in time domain, isnt?
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Reply by fharrisMarch 18, 2021

Ali,


are you phase aligning a sinewave of a local DDS with that of a received complex sinewave? Or are you phase locking to a modulated signal with out an underlying carrier?

I want to make sure we are both looking at same problem.

fred h