Digital Signal Processing Lecture Notes PDF

Eng. Aden Hassan Lecture two A Signal:  Is defined as any physical quantity that varies with time, space or any other independent variable and convey information.  Signal is a function in one or more independent variables.  If a signal depends on only one variable, then it is kn...

Eng. Aden Hassan Lecture two A Signal:  Is defined as any physical quantity that varies with time, space or any other independent variable and convey information.  Signal is a function in one or more independent variables.  If a signal depends on only one variable, then it is know as one dimensional signal. AC power signal, Electrocardiogram are one dimensional signals (we concentrate on this type of signals).  AC power signal Electrocardiogram signal  If a signal depends on two variables then it is known as two dimensional signal. Examples are pictures, and radiological images (X-ray images, MRI images, CT images). CT image Elementary Signals These signals include, unit step, unit impulse, ramp, sinusoidal and exponential functions. The previous signals can be used as building blocks for the modeling of more complex signals. Unit Step Sequence The unit step sequence u[n] is defined as u[n]=1 for n>=0 =0 for n=k =0 for n=0 =0 for n1 sequence, 1>α >0 Representation of Discrete-time Signals: There are different types of representations:  Graphical representation  Functional representation The previous discrete time signal can be represented as: 1+n/3 for -3