matlab problem

urgent!!!!

Objective. The objective of this laboratory exercise is to explore the concepts of sampling and reconstruction of continuous-time (analog) signals from their samples. You will simulate the sampling process of an analog signal using MATLAB, investigate the effect of sampling in the time and frequency domains and introduce the concept of aliasing. Sampling Theorem. For accurate representation of an analog signal xa(t) by its time samples x[n] = xa (nt), two following conditions must be met: 1) The signal xa(t) must be bandlimited, that is, its frequency content (spectrum) must be limited to contain frequencies up to a maximum frequency fmax and no frequencies exists beyond that; 2) The sampling frequency fs must be chosen to be at least twice of fmax, that is fs > 2 fmax or equivalently ws 2wmax Exercise. Consider the following continuous-time signal: xa(t) = 3 sin(20.5t) + 2sin (2x2.5t) The signal contains two frequency components at fi = 0.5Hz and f2 = 2.5Hz. You will explore the effect of aliasing by sampling xa(t) at fs = 4fmax = 10Hz. In MATLAB, explore time-domain by the following plots: The original time signal xa(t), t (0,10). The sampled signal x[n] (discrete-time signal) with fs = 10Hz. The sampled signal superimposed on top of the reconstructed analog signal. Repeat the same experiment with fs = 1Hz, fs = 4Hz, fs = 20Hz. What happens with fs = 2 fmax = 5Hz? Explain the reason if aliasing occurs. Objective. The objective of this laboratory exercise is to explore the concepts of sampling and reconstruction of continuous-time (analog) signals from their samples. You will simulate the sampling process of an analog signal using MATLAB, investigate the effect of sampling in the time and frequency domains and introduce the concept of aliasing. Sampling Theorem. For accurate representation of an analog signal xa(t) by its time samples x[n] = xa (nt), two following conditions must be met: 1) The signal xa(t) must be bandlimited, that is, its frequency content (spectrum) must be limited to contain frequencies up to a maximum frequency fmax and no frequencies exists beyond that; 2) The sampling frequency fs must be chosen to be at least twice of fmax, that is fs > 2 fmax or equivalently ws 2wmax Exercise. Consider the following continuous-time signal: xa(t) = 3 sin(20.5t) + 2sin (2x2.5t) The signal contains two frequency components at fi = 0.5Hz and f2 = 2.5Hz. You will explore the effect of aliasing by sampling xa(t) at fs = 4fmax = 10Hz. In MATLAB, explore time-domain by the following plots: The original time signal xa(t), t (0,10). The sampled signal x[n] (discrete-time signal) with fs = 10Hz. The sampled signal superimposed on top of the reconstructed analog signal. Repeat the same experiment with fs = 1Hz, fs = 4Hz, fs = 20Hz. What happens with fs = 2 fmax = 5Hz? Explain the reason if aliasing occurs