qpsk in rayleigh channel simulation changes everytime you simulate

plot of ber vs enno for qpsk in rayleigh channel using the object rayleighchan changes for each simulation.why is this happening?my code is as follows: % Create Rayleigh fading channel object. chan = rayleighchan(1/10000,0);

% Generate data and apply fading channel. M = 4; % QPSK modulation order hMod = modem.pskmod('M', M,'InputType','bit'); % Create a QPSK modulator hDemod =modem.pskdemod('M',M,'OutputType','bit','DecisionType','hard decision'); % Create a QPSK demodulator % using the modulator tx = randsrc(50000,1,[0 1]); % Generate a random bit stream dpskSig = modulate(hMod, tx); % QPSK modulate the signal fadedSig = filter(chan,dpskSig); % Apply the channel effects

% Compute error rate for different values of SNR. SNR = 0:2:40; % Range of SNR values, in dB. numSNR = length(SNR); BER = zeros(1, numSNR); for n = 1:numSNR rxSig = awgn(fadedSig,SNR(n)); % Add Gaussian noise rx = demodulate(hDemod, rxSig); % Demodulate % Compute error rate. [nErrors, BER(n)] = biterr(tx,rx); end

% Plot BER results. semilogy(SNR,BER,'r*'); legend('Empirical BER'); xlabel('SNR (dB)'); ylabel('BER'); title('Binary QPSK over Rayleigh Fading Channel');

[Wayne King]

Please format your code

[sharvari samant]

plot of ber vs enno for qpsk in rayleigh channel using the object rayleighchan changes for each simulation.why is this happening?my code is as follows:

% Create Rayleigh fading channel object.

chan = rayleighchan(1/10000,0);

% Generate data and apply fading channel.

M = 4; % QPSK modulation order

hMod = modem.pskmod('M', M,'InputType','bit'); % Create a QPSK modulator

hDemod =modem.pskdemod('M',M,'OutputType','bit','DecisionType','hard decision'); % Create a QPSK demodulator

tx = randsrc(50000,1,[0 1]); % Generate a random bit stream

dpskSig = modulate(hMod, tx); % QPSK modulate the signal

fadedSig = filter(chan,dpskSig); % Apply the channel effects

% Compute error rate for different values of SNR.

SNR = 0:2:40; % Range of SNR values, in dB.

numSNR = length(SNR);

BER = zeros(1, numSNR);

for n = 1:numSNR

   rxSig = awgn(fadedSig,SNR(n));   % Add Gaussian noise

   rx = demodulate(hDemod, rxSig);  % Demodulate

   % Compute error rate.

   [nErrors, BER(n)] = biterr(tx,rx);

end

% Compute theoretical performance results, for comparison.

% Plot BER results.

semilogy(SNR,BER,'r*');

legend('Empirical BER');

xlabel('SNR (dB)'); ylabel('BER');

title('Binary QPSK over Rayleigh Fading Channel');

[sharvari samant]

this code is the modified version of the code given in matlab help for dpsk