cascade |
---|

The simplest form is when one system's output is connected only
to another's input. Mathematically,

Inside Collection (Course): ECE 454 and ECE 554 Supplemental reading

Summary: Introduction to the concept of a system, which is a mechanism for manipulating signals. Feedback concepts and superpositions are also briefly mentioned.

*Signals are manipulated by systems*.
Mathematically, we represent what a system does by the notation

Definition of a system |
---|

This notation mimics the mathematical symbology of a function: A system's input is analogous to an independent variable and its output the dependent variable. For the mathematically inclined, a system is a functional: a function of a function (signals are functions).

Simple systems can be connected together--one system's output becomes another's input--to accomplish some overall design. Interconnection topologies can be quite complicated, but usually consist of weaves of three basic interconnection forms.

cascade |
---|

The simplest form is when one system's output is connected only
to another's input. Mathematically,

parallel |
---|

A signal

feedback |
---|

The subtlest interconnection configuration has a system's
output also contributing to its input. Engineers would say the
output is "fed back" to the input through system 2, hence the
terminology. The mathematical statement of the feedback interconnection
is that the feed-forward system produces the output:

- « Previous module in collection Signals Represent Information
- Collection home: ECE 454 and ECE 554 Supplemental reading
- Next module in collection » Discrete-Time Signals and Systems

Comments:"Electrical Engineering Digital Processing Systems in Braille."