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| + | == Causal System == | ||
| − | + | A causal system (non-anticipative system) is one that produces an output that is dependent on either present or past values of 't'. Therefore, a causal system does not produce an output x(t) based on any future value of 't'. Furthermore, we can conclude that all memoryless systems are causal because they only depend on a present value of 't'. | |
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| + | == Non-Causal System == | ||
| − | + | A non-causal system is one that produces an output that is dependent on some future value of 't'. In addition to being dependent on a future value of 't', the system's output may also be dependent on a present or past value of t. | |
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Causal System: | Causal System: | ||
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Non-Causal System: | Non-Causal System: | ||
y(t) = x(t+9) +6 | y(t) = x(t+9) +6 | ||
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The first system is causal since it is dependent on a past value of 't'. However, the second system is non-causal because it depends on a future value of 't'. | The first system is causal since it is dependent on a past value of 't'. However, the second system is non-causal because it depends on a future value of 't'. | ||
Latest revision as of 18:27, 16 September 2008
Causal System
A causal system (non-anticipative system) is one that produces an output that is dependent on either present or past values of 't'. Therefore, a causal system does not produce an output x(t) based on any future value of 't'. Furthermore, we can conclude that all memoryless systems are causal because they only depend on a present value of 't'.
Non-Causal System
A non-causal system is one that produces an output that is dependent on some future value of 't'. In addition to being dependent on a future value of 't', the system's output may also be dependent on a present or past value of t.
Causal System:
y(t) = x(t-9) + 6
Non-Causal System: y(t) = x(t+9) +6
The first system is causal since it is dependent on a past value of 't'. However, the second system is non-causal because it depends on a future value of 't'.
