Unwrap function not operating correctly

B = (:,1:3);
C = (:,4);       % Group packets restart at 0 and finish at a specific number 

group = cumsum(C == 0) + double(C(1) ~= 0); % Splits the groups further 
                                            % into ones then twos then therees etc... 
                                            % [1 1 1 1 1 2 2 2 2 2 2 2 3 3 3 4 4 4]'

Bb = splitapply(@(m) {(unwrap(m/2^15*pi)*2^15/pi)}, B, group); % Splits the groups up and performs the 
                                                               % caculation unwrap(m/2^15*pi)*2^15/pi

Original output input at B

The result of the algorithm can be seen below. Unfortunately, it is not operating correctly as it has a drift in the y-direction. Can anyone provide any insight into how to correct this code?

[Guillaume]

What's the difference between the A used in the splitapply and the B you're talking about (not used in the splitapply).

Example data would be useful.

[Nikolaos Zafirakis]

Sorry that should be B I corrected it.

Example data:

% This is one group
C =[2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2];

B1 =[-29486;-31150;-31500;-30576;-29350;-19632;-24221;-20417;-15841;-11325;-6617;5820;4186;10610;16942;22828;28142;-25680;-29776;-27538;-26586;-26958;-28566;-24044;31398;28060;23746;18618;12744;13482;-32574;-29124;-24850;-19676;-14163;-1173;19956;21032;21166;20836;20613;26955;17893;15253;11699;7629;2945;5079];
B2 =[-14395;-16584;-15732;-11954;-6460;2777;9769;19115;28455;-29054;-22624;-16542;-15596;-14866;-16418;-20092;-25514;-30488;26302;18940;12362;7056;3710;4162;4799;9249;15213;22089;29161;-28100;-7633;-10188;-10056;-7380;-2508;5849;-24876;-27404;-32100;27292;20888;15506;6928;266;-5541;-10183;-13225;-12943];
B3 =[26064;17076;7469;-2122;-10894;-13942;-23308;-26392;-27028;-24904;-20794;-10792;-8302;-1378;5287;10919;15055;21602;17542;15678;12180;7030;762;-1701;-12693;-18910;-23640;-26508;-27304;-21836;12621;5679;-1844;-9298;-15986;-17132;-788;7053;14501;20730;25130;31850;28062;26436;23402;19336;14472;13446];

B = [B1,B2,B3];

figure (1)
plot(B)


group = cumsum(C == 0) + double(C(1) ~= 0); % Splits the groups further 
                                            % into ones then twos then therees etc... 
                                            % [1 1 1 1 1 2 2 2 2 2 2 2 3 3 3 4 4 4]'
Bb = splitapply(@(m) {(unwrap(m/2^15*pi)*2^15/pi)}, B, group); % Splits the groups up and performs the 
                                                               % caculation unwrap(m/2^15*pi)*2^15/pi
B_new = cell2mat(Bb);

figure (2)                                                               
plot(B_new)                                                                                                              

[Guillaume]

Unless, I'm missing something, it seems to work correctly with your example data. This is the output I get:

R2019b (please enter your version to the right of the question).

[Nikolaos Zafirakis]

Hello Guilaume, sorry in the figure I provided,

C =[2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;2;3;3;3;3;3;3;4;4;4;4;4;4;4;4;4;4;4;4]

To break it up further.

Regarding the values the yellow and blue data lines should not surpass +-60000. The red you have plotted is correct, however the yellow and blue have drifted out of the range required. Thus, by splitting the values up further I got a something solution closer to the truth but now the red value has drifted.

I have MATLAB R2019b for some reason it does not let me input it on the web page.