Questions and Comments for

Downsampling in the Frequency Domain

A slecture by ECE student John Sterrett



Please post your reviews, comments, and questions below.



  • Review by Jacob Holtman

There should be a mathematical definition of down sampling and not just a graphical one. Also the points that are kept in the second graph should be explained better and not left to the reader to find. The equations are very well set up and it is easy to follow the logic. Also the example helps to explain why a filter is needed and limitations.


  • Review by Andrew Pawling

I agree that it does need a mathematical definition of down sampling. The plots are good and help illustrate the down-sampling. The Mathematical explanation is very clear and concise. The explanation of why the low-pass filter is needed is also good. Great job!


  • Review by Sahil Sanghani

Great job! The graphs are effectively used to demonstrate your equation derivations. I think the first graph is a little unclear. Maybe describing downsampling with words would help make that graph a little clearer. I really liked your discussion on aliasing and how to prevent it. Overall this was a great slecture.


  • Review by Soonho Kwon

It would have been better to represent a definition of down sampling. Moreover, I liked the plots because it helped me understand what was going on through this slecture. Moreover, having the low-pass filter at the end, explains a lot about this down sampling. Good job.


  • Review by David Klouda

I like the hand-drawn diagrams as they helped to convey the message of the slecture. In the future, it may be helpful to include plots from MATLAB to fully convey your example and back it up with numerical evidence.


  • Review by Botao Chen

I agree with the suggestion to have a mathematical definition. It will help to build a more concrete understanding about how everything is going on. I like your derivation about the downsamplin. Maybe you could talk more about the use of low pass filter in downsampling.


  • Review by Randall Cochran

The slecture was good. As others have said, a mathematical definition of downsampling would have helped. Also, in the first graphical example, clarifying what was happening with the points on the graph would be really helpful. It can be confusing to try and determine what was happening between the left and right graphs. Overall good job though.


  • Review by Fabian Faes

I thought this slecture had a great flow and was explained in great detail which really helped me understand downsampling better. I especially liked the last section of the slecture where the reasoning behind low pass filtering before downsampling is explained to reduce aliasing. There are certain sentences in this slecture that ran off my page which seems very odd but other than that I could not fault it. Great job!


  • Review by Xiaozhe Fan


The overall slecture was very clear. But it is better to show a definition of downsampling, and if you can use some software to draw the graphical instead of doing it by hand, it would be keep your job more perfect. Or maybe you can use matlab to help you getting the graphical examples. I like this slecture.


  • Review by student 10

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