Signal (circuit theory)

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A signal within the context of circuit theory is any information that has value to a particular electronic network. In a more concrete sense, the signals in a circuit are carried as changes in the voltages and currents of the circuit over time. Signals in circuit theory come in two types: analog and digital. While the mechanics of how these signals are stored are identical, their behaviours and uses are in fact quite different.

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[edit] Basic Properties

Any signal in a circuit theory setting can be defined as a scalar time varying value, more commonly recognized in a graph form, with the change in time placed along the bottom and the change in the scalar value along the side. Since the signal can be modeled mathematically in this manner, it becomes very convenient to model mathematical systems as series of differential equations to be solved over the signal graph.

[edit] Signal Types

[edit] Analog Signals

An analog circuit signal is a signal that can assume an infinite number of distinct values (once again represented as voltage or current in the circuit), and carries information in this manner. Some examples of an analog signals in a circuit are sound waveforms carried as a continuously-varying voltage, the standard 60Hz

[edit] Digital Signals

A digital signal can have only 2 values; 1 or 0. These can be represented as a series of bumps, called mountains and valleys. All signals are eventually converted into digital signals as this is the only type of signal circuits can transport.