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Before beginning this homework, review the following [[CT_Fourier_Transform_%28frequency_in_radians_per_time_unit%29|table of CT Fourier transform pairs and properties]], which features the CT Fourier transform in terms of <math>\omega</math> (in radians per time unit). You should have seen each of these in [[ECE301]]. Then compare with the following [[CT_Fourier_Transform_%28frequency_in_hertz%29|table of CT Fourier transform pairs and properties]], which uses the CT Fourier transform in terms of frequency <math>f</math> in hertz. Note that we will use the latter in [[ECE438]]. | Before beginning this homework, review the following [[CT_Fourier_Transform_%28frequency_in_radians_per_time_unit%29|table of CT Fourier transform pairs and properties]], which features the CT Fourier transform in terms of <math>\omega</math> (in radians per time unit). You should have seen each of these in [[ECE301]]. Then compare with the following [[CT_Fourier_Transform_%28frequency_in_hertz%29|table of CT Fourier transform pairs and properties]], which uses the CT Fourier transform in terms of frequency <math>f</math> in hertz. Note that we will use the latter in [[ECE438]]. | ||
| − | ==Question== | + | ==Question 1== |
In [[ECE301]], you learned that the Fourier transform of a step function <math>x(t)=u(t)</math> is the following: | In [[ECE301]], you learned that the Fourier transform of a step function <math>x(t)=u(t)</math> is the following: | ||
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Use this fact to obtain an expression for the Fourier transform <math>X(f)</math> (in terms of frequency in hertz) of the step function. (Your answer should agree with the one given in this [[CT_Fourier_Transform_%28frequency_in_hertz%29|table]].) Justify all your steps. | Use this fact to obtain an expression for the Fourier transform <math>X(f)</math> (in terms of frequency in hertz) of the step function. (Your answer should agree with the one given in this [[CT_Fourier_Transform_%28frequency_in_hertz%29|table]].) Justify all your steps. | ||
| + | ==Question 2== | ||
| + | What is the Fourier transform of <math>x(t)= e^{j \pi t}</math>? Justify your answer. | ||
== Discussion == | == Discussion == | ||
Revision as of 11:15, 24 August 2011
Homework 1, ECE438, Fall 2011, Prof. Boutin
Due Wednesday August 31, 2011 (in class)
Before beginning this homework, review the following table of CT Fourier transform pairs and properties, which features the CT Fourier transform in terms of $ \omega $ (in radians per time unit). You should have seen each of these in ECE301. Then compare with the following table of CT Fourier transform pairs and properties, which uses the CT Fourier transform in terms of frequency $ f $ in hertz. Note that we will use the latter in ECE438.
Question 1
In ECE301, you learned that the Fourier transform of a step function $ x(t)=u(t) $ is the following:
$ {\mathcal X} (\omega) = \frac{1}{j \omega} + \pi \delta (\omega ). $
Use this fact to obtain an expression for the Fourier transform $ X(f) $ (in terms of frequency in hertz) of the step function. (Your answer should agree with the one given in this table.) Justify all your steps.
Question 2
What is the Fourier transform of $ x(t)= e^{j \pi t} $? Justify your answer.
Discussion
Please discuss the homework below.
