How do I decode encrypted data and plot it??

I have some data that is encrypted so that values <1.2V are considered logic 0 and values >2.2V are considered logic 1. The true signal is either 0V (for logic 0) or 3.3V (for logic 1), and any value above or below this threshold will include noise. I am stuck on how to get the values to stay within the threshold and how to plot the new data once it does so.

I have attached the data and my code so far but I am unsure of how to progess. Can I get any help?

time = xlsread('data.csv', 'A2:A201');
pair_1 = xlsread('data.csv', 'B2:B201');
pair_2 = xlsread('data.csv', 'C2:C201');
pair_3 = xlsread('data.csv', 'D2:D201');
pair_4 = xlsread('data.csv', 'E2:E201');

if pair_1 < 1.2 
    
    pair_1 = 0 
if    pair_1 > 2.2
    
    pair_1 = 3.3
    plot(time, pair_1)
end 

end 

Answer 1

[Mitch Lautigar]

You have a couple different ways to do this. I've listed two below to try and help.

Both ways I did it start with the following.

%--------------------------------------------------------------------------------------------------------------------------%

% Predeclarations %

data = readtable('data.csv'); %read in csv file as a table. xlsread is being/has been phased out.

data2 = table2array(data); %gets csv file into an array for easy checking.

%--------------------------------------------------------------------------------------------------------------------------%

%method 1 -- for loops

%this method works because data2 is an array of set size.

% Advantages: Easy to debug, and results are quite viewable.

% Disadvantages: If you are looking at 10k data points, this can become memory intensive.

data_check_array = []; %empty array to stack in checks.

[a,b] = size(data2);

for i = 1:length(data2) %handles each row

stack = [];

for j = 2:b %handles each column ignoring the time value.

if (data2(i,j) >= 1.2) && (data2(i,j) <= 2.2) %this means neither true or false

stack = [stack,0.5];

elseif (data2(i,j) < 1.2) %means false

stack = [stack,0];

else %means true

stack = [stack,1];

end

end %end j for loop

data_check_array = [data_check_array;stack];

end %end i for loop

%--------------------------------------------------------------------------------------------------------------------------%

% method 2 -- Hide and Seek

%This method works because you are only seeking specific numerical values in the table

% Advantages: This method is quick on computations and leads to solid end results

% Disadvantages: This method is much harder to debug.

true_indx = find(data2(:,2:end) > 2.2);

false_indx = find(data2(:,2:end) < 1.2);

[a,b] = size(data2);

check_array(1:a,2:b) = 0.5; %assume all values are not checked to not have to have a null index.

check_array(true_indx) = 1;

check_array(false_indx) = 0;

check_array(:,1) = data2(:,1);

%--------------------------------------------------------------------------------------------------------------------------%

I sadly don't have the capabilities to test this code, but I am confident the logic is good. Hope it helps!