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Project - Data Handling and Interpolation

SSudheer Kumar Devisetti15 Mar 2023

In a laboratory experiment, data of voltage and current has been recorded and the same is attached in an excel file ( Click on this link VI.xlsx ). Read the excel file in the Matlab program and perform the interpolation in the range of -17.3:0.1:0.9. Generate the interactive plot for the interpolated data and store them in a text file.

%import the VI1 file to matlab workspace;
p=xlsread('VI (1).xlsx','Sheet1','A2:B25');
v=p(:,1); %voltage
i=p(:,2); %current
plot(v,i,'rO','MarkerSize',8);
hold on;
grid on;
%interpolating current values
%inter
vi=(-17.3:0.1:0.9); %required voltage range
ii=spline(v,i,vi);
fileid = fopen('spline_values.txt','w'); % new text file
table=[vi;ii];
fprintf(fileid,'%f, %f.\n',table);
fclose(fileid);
plot(vi,ii,'-k','LineWidth',2);
hold on;
figure(1)
xlabel('Voltage')
ylabel('Current')
title('voltage and current','FontSize',20,'BackgroundColor','y');
command window : -

table =

Columns 1 through 9

-17.3000 -17.2000 -17.1000 -17.0000 -16.9000 -16.8000 -16.7000 -16.6000 -16.5000
-28.0000 -28.1734 -24.0000 -19.0000 -15.8685 -14.0000 -12.2353 -10.5022 -9.0000

Columns 10 through 18

-16.4000 -16.3000 -16.2000 -16.1000 -16.0000 -15.9000 -15.8000 -15.7000 -15.6000
-7.8806 -7.1062 -6.5915 -6.2512 -6.0000 -5.7670 -5.5389 -5.3164 -5.1007

Columns 19 through 27

-15.5000 -15.4000 -15.3000 -15.2000 -15.1000 -15.0000 -14.9000 -14.8000 -14.7000
-4.8926 -4.6931 -4.5031 -4.3236 -4.1556 -4.0000 -3.8574 -3.7271 -3.6080

Columns 28 through 36

-14.6000 -14.5000 -14.4000 -14.3000 -14.2000 -14.1000 -14.0000 -13.9000 -13.8000
-3.4991 -3.3993 -3.3076 -3.2228 -3.1440 -3.0701 -3.0000 -2.9328 -2.8682

Columns 37 through 45

-13.7000 -13.6000 -13.5000 -13.4000 -13.3000 -13.2000 -13.1000 -13.0000 -12.9000
-2.8061 -2.7464 -2.6889 -2.6334 -2.5799 -2.5282 -2.4782 -2.4298 -2.3827

Columns 46 through 54

-12.8000 -12.7000 -12.6000 -12.5000 -12.4000 -12.3000 -12.2000 -12.1000 -12.0000
-2.3369 -2.2922 -2.2486 -2.2058 -2.1637 -2.1222 -2.0812 -2.0405 -2.0000

Columns 55 through 63

-11.9000 -11.8000 -11.7000 -11.6000 -11.5000 -11.4000 -11.3000 -11.2000 -11.1000
-1.9596 -1.9193 -1.8792 -1.8394 -1.7999 -1.7608 -1.7223 -1.6843 -1.6469

Columns 64 through 72

-11.0000 -10.9000 -10.8000 -10.7000 -10.6000 -10.5000 -10.4000 -10.3000 -10.2000
-1.6103 -1.5745 -1.5395 -1.5055 -1.4725 -1.4406 -1.4099 -1.3804 -1.3522

Columns 73 through 81

-10.1000 -10.0000 -9.9000 -9.8000 -9.7000 -9.6000 -9.5000 -9.4000 -9.3000
-1.3253 -1.3000 -1.2762 -1.2538 -1.2327 -1.2130 -1.1944 -1.1770 -1.1605

Columns 82 through 90

-9.2000 -9.1000 -9.0000 -8.9000 -8.8000 -8.7000 -8.6000 -8.5000 -8.4000
-1.1450 -1.1304 -1.1164 -1.1032 -1.0906 -1.0784 -1.0667 -1.0552 -1.0441

Columns 91 through 99

-8.3000 -8.2000 -8.1000 -8.0000 -7.9000 -7.8000 -7.7000 -7.6000 -7.5000
-1.0330 -1.0221 -1.0111 -1.0000 -0.9887 -0.9773 -0.9656 -0.9538 -0.9418

Columns 100 through 108

-7.4000 -7.3000 -7.2000 -7.1000 -7.0000 -6.9000 -6.8000 -6.7000 -6.6000
-0.9297 -0.9174 -0.9049 -0.8923 -0.8795 -0.8665 -0.8535 -0.8403 -0.8269

Columns 109 through 117

-6.5000 -6.4000 -6.3000 -6.2000 -6.1000 -6.0000 -5.9000 -5.8000 -5.7000
-0.8135 -0.7999 -0.7862 -0.7724 -0.7585 -0.7445 -0.7304 -0.7162 -0.7019

Columns 118 through 126

-5.6000 -5.5000 -5.4000 -5.3000 -5.2000 -5.1000 -5.0000 -4.9000 -4.8000
-0.6876 -0.6731 -0.6586 -0.6441 -0.6294 -0.6147 -0.6000 -0.5852 -0.5704

Columns 127 through 135

-4.7000 -4.6000 -4.5000 -4.4000 -4.3000 -4.2000 -4.1000 -4.0000 -3.9000
-0.5557 -0.5409 -0.5263 -0.5119 -0.4976 -0.4835 -0.4696 -0.4561 -0.4428

Columns 136 through 144

-3.8000 -3.7000 -3.6000 -3.5000 -3.4000 -3.3000 -3.2000 -3.1000 -3.0000
-0.4299 -0.4174 -0.4054 -0.3937 -0.3826 -0.3721 -0.3621 -0.3527 -0.3439

Columns 145 through 153

-2.9000 -2.8000 -2.7000 -2.6000 -2.5000 -2.4000 -2.3000 -2.2000 -2.1000
-0.3359 -0.3285 -0.3219 -0.3161 -0.3112 -0.3070 -0.3038 -0.3016 -0.3003

Columns 154 through 162

-2.0000 -1.9000 -1.8000 -1.7000 -1.6000 -1.5000 -1.4000 -1.3000 -1.2000
-0.3000 -0.3007 -0.3021 -0.3037 -0.3052 -0.3062 -0.3064 -0.3053 -0.3026

Columns 163 through 171

-1.1000 -1.0000 -0.9000 -0.8000 -0.7000 -0.6000 -0.5000 -0.4000 -0.3000
-0.2978 -0.2906 -0.2806 -0.2674 -0.2507 -0.2300 -0.2050 -0.1752 -0.1404

Columns 172 through 180

-0.2000 -0.1000 0 0.1000 0.2000 0.3000 0.4000 0.5000 0.6000
-0.1000 -0.0559 -0.0182 0.0007 -0.0002 0.0002 0.0129 0.1700 1.2300

Columns 181 through 183

0.7000 0.8000 0.9000
10.0433 39.0701 101.1102

PCHIP METHOD
p=xlsread('VI (1).xlsx','Sheet1','A2:B25');
v=p(:,1); %voltage
i=p(:,2); %current
plot(v,i,'-kO','MarkerSize',10,'LineWidth',2);
grid on ;
hold on;
%%interpolation using pchip
vi=(-17.3:0.1:0.9);
ii_p=pchip(v,i,vi)
fileid = fopen('pchip_values.txt','w'); % new text file
table=[vi;ii_p]
fprintf(fileid,'%f, %f.\n',table);
fclose(fileid);
plot(vi,ii_p,'r-','MarkerSize',6,'LineWidth',1);
figure(1);
grid on ;
hold on;
xlabel('Voltage')
ylabel('Current')
title('voltage and current ','PCHIP Method','FontSize',20,'BackgroundColor','y');
command window : -

-17.3000 -17.2000 -17.1000 -17.0000 -16.9000 -16.8000 -16.7000 -16.6000 -16.5000
-28.0000 -26.7500 -24.0000 -19.0000 -16.1414 -14.0000 -12.0069 -10.2540 -9.0000

Columns 10 through 18

-16.4000 -16.3000 -16.2000 -16.1000 -16.0000 -15.9000 -15.8000 -15.7000 -15.6000
-8.1511 -7.4352 -6.8439 -6.3684 -6.0000 -5.6987 -5.4281 -5.1851 -4.9666

Columns 19 through 27

-15.5000 -15.4000 -15.3000 -15.2000 -15.1000 -15.0000 -14.9000 -14.8000 -14.7000
-4.7696 -4.5911 -4.4279 -4.2770 -4.1354 -4.0000 -3.8702 -3.7475 -3.6316

Columns 28 through 36

-14.6000 -14.5000 -14.4000 -14.3000 -14.2000 -14.1000 -14.0000 -13.9000 -13.8000
-3.5225 -3.4199 -3.3237 -3.2338 -3.1499 -3.0721 -3.0000 -2.9322 -2.8673

Columns 37 through 45

-13.7000 -13.6000 -13.5000 -13.4000 -13.3000 -13.2000 -13.1000 -13.0000 -12.9000
-2.8049 -2.7451 -2.6876 -2.6323 -2.5791 -2.5277 -2.4780 -2.4299 -2.3831

Columns 46 through 54

-12.8000 -12.7000 -12.6000 -12.5000 -12.4000 -12.3000 -12.2000 -12.1000 -12.0000
-2.3377 -2.2933 -2.2498 -2.2072 -2.1651 -2.1235 -2.0822 -2.0411 -2.0000

Columns 55 through 63

-11.9000 -11.8000 -11.7000 -11.6000 -11.5000 -11.4000 -11.3000 -11.2000 -11.1000
-1.9588 -1.9175 -1.8763 -1.8352 -1.7945 -1.7542 -1.7144 -1.6753 -1.6370

Columns 64 through 72

-11.0000 -10.9000 -10.8000 -10.7000 -10.6000 -10.5000 -10.4000 -10.3000 -10.2000
-1.5996 -1.5631 -1.5278 -1.4938 -1.4611 -1.4298 -1.4002 -1.3723 -1.3462

Columns 73 through 81

-10.1000 -10.0000 -9.9000 -9.8000 -9.7000 -9.6000 -9.5000 -9.4000 -9.3000
-1.3221 -1.3000 -1.2795 -1.2601 -1.2417 -1.2241 -1.2073 -1.1913 -1.1759

Columns 82 through 90

-9.2000 -9.1000 -9.0000 -8.9000 -8.8000 -8.7000 -8.6000 -8.5000 -8.4000
-1.1611 -1.1468 -1.1329 -1.1194 -1.1061 -1.0930 -1.0800 -1.0670 -1.0540

Columns 91 through 99

-8.3000 -8.2000 -8.1000 -8.0000 -7.9000 -7.8000 -7.7000 -7.6000 -7.5000
-1.0409 -1.0276 -1.0140 -1.0000 -0.9858 -0.9716 -0.9574 -0.9433 -0.9291

Columns 100 through 108

-7.4000 -7.3000 -7.2000 -7.1000 -7.0000 -6.9000 -6.8000 -6.7000 -6.6000
-0.9149 -0.9008 -0.8867 -0.8727 -0.8587 -0.8448 -0.8309 -0.8171 -0.8034

Columns 109 through 117

-6.5000 -6.4000 -6.3000 -6.2000 -6.1000 -6.0000 -5.9000 -5.8000 -5.7000
-0.7897 -0.7762 -0.7627 -0.7494 -0.7361 -0.7230 -0.7100 -0.6972 -0.6844

Columns 118 through 126

-5.6000 -5.5000 -5.4000 -5.3000 -5.2000 -5.1000 -5.0000 -4.9000 -4.8000
-0.6719 -0.6595 -0.6472 -0.6351 -0.6232 -0.6115 -0.6000 -0.5887 -0.5776

Columns 127 through 135

-4.7000 -4.6000 -4.5000 -4.4000 -4.3000 -4.2000 -4.1000 -4.0000 -3.9000
-0.5667 -0.5560 -0.5454 -0.5351 -0.5248 -0.5147 -0.5048 -0.4949 -0.4852

Columns 136 through 144

-3.8000 -3.7000 -3.6000 -3.5000 -3.4000 -3.3000 -3.2000 -3.1000 -3.0000
-0.4755 -0.4659 -0.4563 -0.4468 -0.4373 -0.4278 -0.4184 -0.4089 -0.3994

Columns 145 through 153

-2.9000 -2.8000 -2.7000 -2.6000 -2.5000 -2.4000 -2.3000 -2.2000 -2.1000
-0.3898 -0.3802 -0.3706 -0.3608 -0.3510 -0.3411 -0.3310 -0.3208 -0.3105

Columns 154 through 162

-2.0000 -1.9000 -1.8000 -1.7000 -1.6000 -1.5000 -1.4000 -1.3000 -1.2000
-0.3000 -0.2898 -0.2802 -0.2711 -0.2624 -0.2539 -0.2455 -0.2370 -0.2284

Columns 163 through 171

-1.1000 -1.0000 -0.9000 -0.8000 -0.7000 -0.6000 -0.5000 -0.4000 -0.3000
-0.2194 -0.2099 -0.1998 -0.1889 -0.1771 -0.1643 -0.1504 -0.1351 -0.1183

Columns 172 through 180

-0.2000 -0.1000 0 0.1000 0.2000 0.3000 0.4000 0.5000 0.6000
-0.1000 -0.0643 -0.0192 0 0 0.0007 0.0126 0.1700 1.2300

Columns 181 through 183

0.7000 0.8000 0.9000
8.8543 20.7526 26.9384

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