Questions and Comments for Discrete-time Fourier transform (DTFT) of a sampled cosine

A slecture by ECE student Yijun Han



Please post your reviews, comments, and questions below.



  • Review by Miguel Castellanos

Both of your computations are clear, and using the periodicity of cosine in the second computation helps illustrate why aliasing occurs with the second sampling period. In your conclusion, be sure to mention what axis you are rescaling. Nice job!


  • Review by Fabian Faes

I enjoyed the flow of this slecture and how the graphs fitted well with the mathematics described. However in the case of the frequency below the Nyquist rate I think it would have been beneficial to state that frequency shifting occurs due to not fitting withing 0 and pi. I did see that it was stated in the conclusion which I think is good but I still think it should be mentioned at the time of use. Overall a great job!


  • Review by Hyungsuk Kim
    • Both sampling above the Nyquist rate and below the Nyquist rate are well explained and organized. And graphs are very helpful to understand the difference between sampling above and below the Nyquist rate.

  • Review by David Klouda

Your derivations for each of the cases are very easy to understand and have given me a better feel for the topic. The slecture was very well organized into the appropriate sections.


  • Review by Xian Zhang

Good job! You have really clear organization of the material and detailed explanation about all the concepts. It helps me a lot for the following exams. And also the conclusion section is really helpful.


  • Review by Ryan Johnson

Very clear explanation on the subject. It is very clear you have an excellent grasp of the subject matter. The conclusion was spot on. Excellent job overall!



  • Review by Matt Miller

The diagrams made the slecture very easy to follow, however some of the math sections could use better explanations to accompany the math.


  • Review by Student 8
    • Author answer here

  • Review by Student 9
    • Author answer here

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