Continuous and discrete, periodic and aperiodic signals, impulse, unit step signals. Spectrum representation of a signal. Fourier series representation of periodic signals. System concept. Continuous and Discrete Finite Impulse Response (FIR) Systems. Linear Time Invariant (LTI) Systems. Impulse response and Frequency response of LTI systems. Fourier transform of aperiodic and periodic signals. Filtering in time and frequency domain. Sampling of continuous signals. Aliasing. Bandlimited reconstruction, interpolation. Basic Amplitude Modulation.