matlab 4PSK

4PSK (4-Phase Shift Keying) is a digital modulation scheme used in communication systems. In MATLAB, 4PSK modulation can be implemented using the 'pskmod' and 'pskdemod' functions.

The 'pskmod' function generates a complex signal with a specified phase shift based on the binary input data. For 4PSK modulation, the input data is a binary sequence and the phase shift values are {0, pi/2, pi, 3*pi/2}.

The 'pskdemod' function demodulates the received signal back to the original binary sequence. It takes in the received signal and the phase shift values as input and outputs the demodulated binary sequence.

Here is an example code for implementing 4PSK modulation and demodulation in MATLAB:

% 4PSK modulation
M = 4; % Number of phases
data = randi([0 1], 100, 1); % Binary input data
txSignal = pskmod(data, M, pi/M); % 4PSK modulated signal

% 4PSK demodulation
rxSignal = awgn(txSignal, 10); % Add noise to the signal
rxData = pskdemod(rxSignal, M, pi/M); % Demodulate the signal
bitErrorRate = sum(xor(data, rxData))/length(data); % Compute bit error rate

disp(['Bit error rate: ' num2str(bitErrorRate)]);

This code generates a random binary sequence of length 100 and modulates it using 4PSK modulation. It then adds Gaussian noise to the signal and demodulates it back to the original binary sequence. Finally, it computes the bit error rate of the demodulated data compared to the original data.