MATLAB: It shows error (NRZ encoder) : “Vectors must be the same lengths in plot(t,s).”

% Performs NRZI encoding on a bit string. It assumes each signal element

% is 0.5 sec giving 2 bps data rate.

clear;

bits=[1 1 1 1 1 1 1 1 1 1 1]; % input string

numOfBits = length(bits); % store no of bits in string

sampTime = 0.001; % sample time

endTime = numOfBits-sampTime; % required end time for given bit string

t=0:sampTime:10; % x-axis

done=0; % flag to assist in voltage inversion

j = 1; bit = 1;

prevVol = -1; % initial voltage (-ve)

for i = 0:sampTime:endTime

if(floor(i)+1 ~= bit)

% checks whether in the same bit

bit = bit + 1;

done = 0;

end;

if(bits(bit) == 0)

% Maintains voltage for bit 0

s(j) = prevVol;

else

if(~done)

% Inverts voltage for bit 1

s(j) = -1*prevVol;

prevVol = s(j);

done = 1;

j = j + 1;

continue;

end;

s(j) = s(j-1); % Maintains voltage for a signal element

end;

j = j + 1;

end;

% plots the signal

plot(t,s);

axis([0 numOfBits -3 3]);

xlabel('Time (s)');

ylabel('Voltage');