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EQ adaptive DC removal

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This commit is contained in:
Silas Oettinghaus
2024-08-16 10:21:01 +02:00
parent 793a5b7efd
commit 17a1dfbbd5
2 changed files with 12 additions and 4 deletions
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11
Classes/04_DSP/FFE_DCremoval.m
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@@ -19,6 +19,7 @@ classdef FFE_DCremoval < handle
epochs_dd epochs_dd
mu_dc mu_dc
dc_buffer_len
constellation constellation
@@ -40,11 +41,14 @@ classdef FFE_DCremoval < handle
options.epochs_dd = 5; options.epochs_dd = 5;
options.mu_dc = 0.05; options.mu_dc = 0.05;
options.dc_buffer_len = 1;
options.decide = false; options.decide = false;
end end
assert(options.dc_buffer_len>0);
fn = fieldnames(options); fn = fieldnames(options);
for n = 1:numel(fn) for n = 1:numel(fn)
obj.(fn{n}) = options.(fn{n}); obj.(fn{n}) = options.(fn{n});
@@ -100,8 +104,7 @@ classdef FFE_DCremoval < handle
x = [zeros(floor(obj.order/2),1); x; zeros(obj.order,1)]; x = [zeros(floor(obj.order/2),1); x; zeros(obj.order,1)];
err = 0; err = 0;
% e_dc_buffer = NaN(100,1); e_dc_buffer = NaN(obj.dc_buffer_len,1);
e_dc_buffer = NaN(1,1);
e_dc_est = 0; e_dc_est = 0;
for epoch = 1 : epochs for epoch = 1 : epochs
@@ -130,6 +133,10 @@ classdef FFE_DCremoval < handle
obj.e = obj.e - err(symbol) * U / normalizationfactor; % Weight update rule of NLMS obj.e = obj.e - err(symbol) * U / normalizationfactor; % Weight update rule of NLMS
end end
%Update the dc estimation every n-th symbol. This is a
%trivial implementation of parallel EQ´s where the
%errors are not apparent in every step. See Silas OFC
%2023 "MPI mitigation adaptive DC removal"
if mod(symbol,length(e_dc_buffer)) == 0 if mod(symbol,length(e_dc_buffer)) == 0
e_dc_buffer(1) = e_dc_est - obj.mu_dc * err(symbol); e_dc_buffer(1) = e_dc_est - obj.mu_dc * err(symbol);
e_dc_buffer = circshift(e_dc_buffer,1); e_dc_buffer = circshift(e_dc_buffer,1);

3
projects/MPI_August/EQ_development.m
View File

@@ -8,9 +8,10 @@ Bits = load("projects/MPI_August/bits.mat","Bits");
Bits = Bits.Bits; Bits = Bits.Bits;
mdc = [1e-3,1e-2,2e-2,3e-2,4e-2,5e-2,1e-1]; mdc = [1e-3,1e-2,2e-2,3e-2,4e-2,5e-2,1e-1];
mdc = [0.6, 0.7, 0.8, 1, 1.2];
for m = 1:numel(mdc) for m = 1:numel(mdc)
Eq = FFE_DCremoval("epochs_tr",5,"epochs_dd",5,"len_tr",4096*2,"mu_dd",1e-4,"mu_tr",0,"order",25,"sps",2,"decide",0,"mu_dc",mdc(m)); Eq = FFE_DCremoval("epochs_tr",5,"epochs_dd",5,"len_tr",4096*2,"mu_dd",1e-4,"mu_tr",0,"order",25,"sps",2,"decide",0,"mu_dc",mdc(m),"dc_buffer_len",112);
[EQ_sig] = Eq.process(Scope_sig,Symbols); [EQ_sig] = Eq.process(Scope_sig,Symbols);
%%%%% DEMAP %%%%%% %%%%% DEMAP %%%%%%