Lecture 1.pptx - Signals and Systems Lecture1 1 Introduction to signals and systems Signals and systems A signal is a pattern of variation of a physical

# Lecture 1.pptx - Signals and Systems Lecture1 1...

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Signals and Systems Lecture1 1
2 Introduction to signals and systems Signals and systems A signal is a pattern of variation of a physical quantity Signals are all around us. Examples include acoustical, electrical and mechanical signals Signals may depend on one or more independent variables. As the name implies, one-dimensional signals depend on one independent variable. An example is the location of a particle moving in a rectilinear motion, in which case the independent variable is time, t. Two dimensional signals depend on two independent variables. An example is a picture that varies spatially, in which case the independent variables are the spatial coordinates, x and y
3 A system processes signals. For example, a compact disc (CD) player is a system that reads a digital signal from a CD and transforms it into an electrical signal. The electrical signal goes to the speaker, which is another system that transforms electrical signals into acoustical signals. Many signals contain information. Other signals are used only to transport energy. For example, the signal from a wall socket is boring in terms of information content, but very useful for carrying energy.
4 Signals can be categorized as analog, discrete or digital. They are summarized as follows: Analog signals: signals that vary continuously in amplitude and time. The independent variable is not necessarily time, it could also be a spatial coordinate. Discrete-time signals: signals that have continuous amplitude but only exist at discrete times. These signals are represented as sequences of numbers. Digital signals: signals that have discrete amplitude and time. These signals are represented by sequences of numbers with finite precision. They are used when processing information by computer.
5 We will often be interested in converting signals from one type to another.

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