Plotting QPSK Signal Waveforms Using MATLAB

Under the specified conditions of a 2 Baud information rate and 20 Hz carrier frequency, this MATLAB implementation demonstrates how to plot QPSK signal waveforms in the time domain. The waveform visualization helps in understanding the characteristic variations and properties of QPSK signals.

Key implementation aspects include generating quadrature phase shift keying modulation by mapping binary data to four distinct phase states (0°, 90°, 180°, 270°), creating time vectors synchronized with symbol periods, and employing sinusoidal carrier multiplication for waveform generation. The code utilizes MATLAB's plotting functions to display the modulated signal's amplitude variations against time, illustrating phase transitions at symbol boundaries.

Critical functions involved: digital modulation techniques, carrier waveform synthesis, time-domain signal plotting, and phase-state mapping algorithms. The implementation handles symbol-to-phase mapping, carrier signal generation using trigonometric functions, and proper time-axis scaling for accurate waveform representation.