Signals and Systems, basic graphs

In summary, the conversation discusses a new course on Theory of Signals and the confusion the speaker has encountered while trying to understand the different types of signals. They specifically mention the four functions shown in an image and ask for clarification on the vertical lines connecting the points. The response explains that the first three graphs represent continuous time and/or value signals, with the vertical lines serving as visual aids for understanding. The fourth graph represents a discrete time and value signal. The conversation ends with the speaker thanking the expert for clearing up their confusion.
  • #1
Bassalisk
947
2
So I am 2nd year now and we started this new course Theory of Signals.

Already I bumped into a wall when it came to understand basic stuff.

Here is what I mean
[PLAIN]http://pokit.org/get/0864633c869b647116b980428a07d4f1.jpg [Broken]

Here we have 4 functions, each representing one type of signal.

1st one I understand. Its a continuous function, defined at every point.

2nd one reminds me of a plotted sequence. But the thing that confuses me is that vertical line connecting abscissa and the value of the signal.

Does that line represent something? Or is it just for visual purpose?

Same question for the 3rd graph. It is even more confusing. It goes zig-zag. Again what do those vertical lines connecting 2 parts of graph represent?
 
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  • #2
These are the four types of signals:
1st one you got right, continuous time continuous value
2nd one is a discrete time continuous value. The lines are just there to make it easier to see at what time each point represents. In MatLab you make those plots by using stem(x,y).
3rd one is a continuous time discrete valued signal. The vertical lines just represent a jump from one value to another. The signal really is just the horizontal lines, but when you plot it the software connects the data points so you get those jumps.
4th is a discrete time discrete valued signal.

Discrete time signals can be obtained by sampling continuous time signals.
Discrete value signals can be obtained by quantization of a continuous valued signal.
 
  • #3
Thank you for clearing this confusion for me. I just finished with my math class and I still have my math goggles on. That is why I found this confusing.
 

1. What are signals and systems?

Signals refer to any physical quantity that varies with time or space. Systems are mathematical models used to describe how signals are processed or transformed. Together, signals and systems form the basis for understanding and analyzing various engineering and scientific phenomena.

2. What are the types of signals and systems?

Signals can be classified as continuous-time or discrete-time, depending on whether they are defined for all values of time or only at discrete intervals. Systems can be categorized as linear or nonlinear, time-invariant or time-varying, and causal or non-causal.

3. What are the basic graphs used in signals and systems?

The most commonly used graphs in signals and systems are time-domain graphs, frequency-domain graphs, and pole-zero plots. Time-domain graphs plot the amplitude of a signal against time, while frequency-domain graphs represent the amplitude of a signal at different frequencies. Pole-zero plots show the locations of poles and zeros in the complex plane, which describe the behavior of a system.

4. How are signals and systems related to each other?

Signals and systems are closely related because a system operates on a signal to produce an output signal. This output signal can then be fed into another system, creating a chain of systems that can be used to model and analyze complex physical phenomena.

5. What is the importance of signals and systems in science?

Signals and systems are fundamental concepts in various fields of science and engineering, such as telecommunications, control systems, signal processing, and image and audio processing. They provide a framework for understanding how physical systems behave and how signals can be manipulated for various purposes, making them essential for developing new technologies and solving real-world problems.

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