Hello Bogdan, Yes, that would be a good start. You can also browse Stephen Wolfram's Elementary Introduction to the Wolfram Language to get a feel for the language.

If you get stuck with any particular function, you will find more information about it at reference.wolfram.com.

Hope this helps, Abrita

Hi Mariusz. Thanks for putting the time to create this really cool course. I have a bit of a problem with Quiz 1 from the online course. Are you guys sure that the system is identifying correctly the right answers? Thanks!

Bogdan, yes, there clearly is a problem with Quiz 1. Thanks for reporting it!

I must admit that confuses me, that you would get different responses to the quiz questions at different times. Let me check on your quiz results, and we'll reach out to you directly if there is any issue.

Hello @Arturo Pazmino. We plan to send the certificates out at the end of this week. Thank you for your patience!

Hi, I have a question about the certificates, I have not gotten mine, are you still working on these certificates? or is there any other reason for me not getting the certificate?

Thank you, Jamie!

Hi, all.

I was able to see the links for Quiz 7 and Quiz 8 through a different browser.

Hi, I have a few questions about the quiz: Quiz3 Q10 in my framework, I think x[n] should be delta[n]-delta[n-1]+2delta[n-3], then I got the correct answer, otherwise, even the length of convolve won't match...

Quiz4 Q4, the answer differs from the defination in course video, where there should be a factor of 2Pi times the "correct" answer.

Quiz4 Q5, I'm not sure if the answer is based on a different defination of FT, because I won't get the coefficient of sqrt[2/Pi]

And by the way, I pass all the quizzes, but how can I get the cetification doc? like a PDF version?

The missing L31 course video is a known issue that we expect to resolve by next week. I want to remind our Daily Study Group participants that logging watched videos in the course is NOT a requirement for your completion certificate. As a Study Group participant, you need only to pass the course quizzes.

Hello, to the staff, could you please double check the "correct" answers for Quiz 6. Thanks.

@Arturo Pazmino, we have double checked Quiz 6, and the correct answers all check out OK.

If you are experiencing something in the course that doesn't look right, please report it to us at wolfram-u@wolfram.com. Thank you!

Quiz 8 has been released as part of the course framework made available to our Study Group participants. Please check your recording notification email sent today and upcoming reminder emails for your link to the pre-released course framework.

I have two questions:

(1) In the interface for this community share, next to the "Add Notebook" icon is an icon to add a code sample. When I place my cursor over it, it states "Code Sample < pre> < code> Ctrl+K". Please explain exactly how to use this to enter a readable code sample. When I try it, I get the same thing as when I just copy and paste. (I am using the Google Chrome browser.) For example, I get the following:

Subscript[X, \[Delta]](j \[Omega])=1/(2 \[Pi]) \[ScriptCapitalF]{x(t)}*\[ScriptCapitalF]{Subscript[x, \[Delta]](t)}

(2) In file L30_Sampling.nb, I have two questions about the derivation following the cell that states "The Fourier transform of the signal Subscriptx, [Delta] may now be obtained by making use of the Fourier transform time-multiplication theorem (symbol * denotes convolution):" In the first line of the derivation should the argument of the rightmost Fourier transform be Subscript[Delta], T rather than Subscriptx, [Delta] ? Second, please show the detailed steps used to derive the Fourier transform of Subscript[Delta], T as shown in the second line of the derivation. (I assume linearity is used so that the derivation involves transforming the individual terms in the definition of Subscript[Delta], T.)

The links of all recordings of the study sessions can be found on this page.

The link you're looking for can be found here.

In both of today's lessons - Lessons 26 and 27, about Z-transforms and inverse Z-transforms - the functionTransferFunctionModel (https://reference.wolfram.com/language/ref/TransferFunctionModel.html) was used to get zeros/poles of a function, but there was no comment or explanation of the function.

It seems to be a very useful and versatile function. It is also used in Lessons 32 and 33, so perhaps it will be explained more in connection to these lessons?

Thanks Mariusz for the notebook. I'm looking forward to the forthcoming lessons when TransferFunctionModel and BodePlot are used again.

Now that this Signals, System and Signal Processing Study Group/Course is soon at the end, I will use the knowledge obtained to go on using the more advanced features of TransferFunctionModel - and similar functions - to learn more about Control Systems.

(I hope there will be a Wolfram U Study Group/Course in Control Systems soon. Is so, sign me up!)

Works fine for me on the Wolfram Cloud

RSolveValue[y[n] - \[Alpha] y[n-1] == 0, y[n], n]
(* \[Alpha]^(-1 + n) C[1] *)

Most likely you have an existing definition for y or \[Alpha]. Try ClearAll["Global`*"] or "Restart Session" from the "Evaluation" menu, or Quit[].

Could you please release the Vid for June 1st, as it is still not available.

I'm trying without success to maximize a piecewise function for t > 0. How do I do it? My failed code and output is attached as file ''MaximizePiecewiseFunction_GDorfman_2jun22.nb".

Attachments:

MaximizePiecewis...nb

In case you missed today's online session, we've released six of the eight course quizzes, for the material covered during the first three weeks of this Study Group. Successful completion of all eight quizzes is required to earn a certificate. Check your recording notification email today for links to the quizzes.

Looking forward to any discussion, but please send any technical questions about the auto-graded quizzes by email to wolfram-u@wolfram.com, so we can address those directly. Also, we ask that everyone refrain from discussing specific quiz questions on this Community forum. Thanks!

Can we get Fridays recording please (Week 2 Review and Fourier Series)

Super! Thank you Mariusz.

Same here.

I copied the following as input text. Without attaching the notebook, how do I copy and post WL input like this to our community group so it is more readable and also easy for readers to copy and execute in a notebook?

GraphicsGrid[Table[
  DiscretePlot[((2/3)^(n/2) Subscript[\[ConstantC], 1] + (-1)^
       n (2/3)^(n/2) Subscript[\[ConstantC], 2]) UnitStep[n], {n, -5, 
    20}, PlotRange -> {-2, 2}, PlotStyle -> PointSize[0.02`], 
   AxesLabel -> {n, y}, ImageSize -> {400, 400}, 
   PlotLabel -> ("\!\(\*SubscriptBox[\(\[ConstantC]\), \(1\)]\) = " <>
       ToString[N[Subscript[\[ConstantC], 1], 2]] <> 
      ", \!\(\*SubscriptBox[\(\[ConstantC]\), \(2\)]\) = " <> 
      ToString[
       N[Subscript[\[ConstantC], 2], 2]])], {Subscript[\[ConstantC], 
   1], {-1, 1/2, 3/2}}, {Subscript[\[ConstantC], 
   2], {-1, 1/3, -3/2}}]]

Thanks Zbigniew for bringing this up.

Zbigniew Kabala: Yeah ... Solutions to Initial Value Problems with jump/step functions as input (non-homogeneous term) are defined in terms of Heaviside Functions in WL & Mathematica. These solutions are not defined at the jump points ... what means that the solution is not continuous at these points. This is NOT CONSISTENT with the requirement that solutions to DEs must be continuous. How do we reconcile the use of Heaviside Function with the fact that SOLUTIONS (functions satisfying the Differential Equation) MUST be differentiable at every point? This kind of trouble would not occur if the solutions were given in terms of the Step Functions instead. I remember questioning something like this in a previous "Daily Study Group" on Differential Equations ... "Week Review" ... the speaker at that time did not seem to get the point or I was not able to make the point clear. It may be a convenience for further dealing with the "Convergence Theorems" when applying "Fourier Series" or "Fourier Transforms". Of course this choice does not seems to me that change any of these mathematical inconsistencies. Thanks for bringing this point back to discussion! Best regards!

Hi Doug, the convolution video is actually an outlier in terms of how much it differs from the lesson notebook. Most videos will stay much closer to the text in the notebooks.

The reason for the difference you observed is the nice explanation of convolution as a superposition of responses to scaled and shifted pulses that was added to the video but is missing in the notebook.

So, here is a notebook that re-creates that part of the video.

Hi Doug, it is my understanding, that CNNs contain a layer or more in which a discrete-time convolution operation with a finite number of fixed or learned coefficients creates the inputs to the next layer. We will be discussing discrete-time convolution shortly.

Thanks, Mariusz. I really appreciate it. BTW, I wonder why Mathematica gives me different results of integration that it does for you? I'll try to figure it out and will let you know.

I'm a little confused about the solution to Exercise 6 (the last) in L07CTSolutionMethods.

Find the solution of the following nonhomogeneous differential equation with given initial conditions:

y''(t)+Sqrt[2]y'(t)+y(t)=sin(t), 	y'(0)=0, y(0)=0

The forcing function is sin(t) but in the solution the DSolveValue has the equation with "Sin[t] * UnitStep[t]" (i.e. UnitStep[t] is added):

DSolveValue[{y''[t] + Sqrt[2] y'[t] + y[t] == Sin[t] UnitStep[t], 
   y'[0] == 0, y[0] == 0}, y[t], t] // Simplify

Why is the UnitStep function added to the equation here? Are there some underlying assumptions about this question that I've missed?

To what extent the course's focus is going to continue on electrical circuits (this is seemingly such an old content XIX/XX c. :-) ) ? Such focus seems unnecessary (and it may be create a barrier for some people) in order to get at signal types/characteristics and signal processing. Though I am an electrical engineer by original training, my current interest in signal processing is more general. My specific interest is from the perspective of analyzing human neuro-physiological signals and the systems I study are human-machine systems. Hence my domain agnostic interest in signal processing.

Also: Are we going to get to multiresolution wavelet analysis?

Thanks - Jacek

Thanks @Mariusz Jankowski Thanks for explaining. The current study group content is very much what I was learning in mid-1980s in Poland (Politechnika Lódzka) when I studied electrical engineering and control systems, just without Mathematica :-) . A nice refresher! (I moved later to human factors engineering and psychology).

Do you know of any study group which would focus on multiresolution analysis using wavelets (discrete)?

Hi Mitch, the answer was Kirchhoff's laws.

The Exercises and Example notebooks for lessons 6..14 are missing in the Exercises and Examples folder. Will they be added later, or are there simply no notebooks for these lessons?

(I like to prepare for the lessons in advance since much of this is new for me, and/or I have forgot some of the college lessons in the 70s...)

/Hakan

I just noticed that all the exercise notebooks have the solutions, so I guess there is nothing to turn in.

Hi Wilfredo, thanks for the additional links and great suggestions for additional course materials. As I posted earlier, Oppenheim's version is my preferred Signals and Systems reference. There are of course other notable authors in this area - Lathi in particular. Oppenheim's recordings are great but be forewarned, their length, each a typical class session, requires a level of commitment that many nowadays find challenging. However, if you are up to it, absolutely, dive in and learn from one of the premier educators in this area of electrical engineering. I am also a great fan of your other suggestion - the Foundations of Signal Processing by Vetterli and Kovacevic. As the title suggests, it truly is an introduction to the mathematical foundations of signal processing and the most recent attempt to redefine how this topic is taught.

TO EVERYONE (STUDENTS) Above I place some links. I do recommend checking the MIT free Course on Signal and system Why? it aligns with this study group in the Topics, you can download each Chapter and Video and the professor is Professor Oppenheim. I am sure you can find the entire Book not chapter by Chapter.

To download faster use "Chrome" or IE 11 (not Microsoft edge) so that you use "right click and save the MP4 videos". Any Other course free in the MIT you can download videos and resources. They have over 600 courses free (good for refresh material if you have attended any engineering school).

If you use Microsoft edge, you will not see the download link and will default to ply the Video. Also check this link https://fourierandwavelets.org/ and download the free two Books and the Matematica books with the PDF. They will complement the learning on this study group. The Workbook ZIP/TAR provide is just the syntax under Mathematica along with the exercise. I will attend the Fridays class and sporadic during he week.

https://ocw.mit.edu/courses/res-6-007-signals-and-systems-spring-2011/pages/introduction/ Instructor: Prof. Alan V. Oppenheim
Course Number: RES.6-007 Departments: Supplemental Resources
As Taught In: Spring 2011

@Mitchell Sandlin we should be able to share the PDF versions. We will try to add them to the download folder soon.

Hi Jacek, An email was just sent out with a link to download the exercises. Please check again.

Hi Wilfredo, I will ask our team to include Poll questions if possible. As for the cell brackets, in the notebook, if you evaluate the following, it will hide the cell brackets for all your notebooks: SetOptions[$FrontEnd, ShowCellBracket -> False]

Hello @wilfredo henriquez , As you are migrating to Mathematica, you might find this video helpful to get started with Wolfram Notebooks: Learn to Use a Notebook on the Desktop

Hi Jacek, the exercises start with Lesson 2, we did not create an exercise notebook for the introductory lesson.

Jacek, That's correct. There are no exercises for Lesson 1 (Introduction). For today's session, you have L02 exercises.We covered L01 and L02 today.

Hi Jacek, in general the notebooks may have more examples compared to the presentation. Here is the missing example for L09:

Hi, to download material, please check box both folder and look the Top Right Corner to DOWBLOAD ALL. The file is a ZIP/TAR folder compress with all the folders and exercise.

Click on "Make your own copy" to open a copy of the notebook in Cloud. Then File> Download. You could also click on a cell bracket here in the notebook, copy the cell and paste it into your own notebook.

Leila, I have the same problem that I cannot attend daily, but really would like to audit. So I signed up and will try to attend when possible. Fridays, I am available and usually mondays and wednesdays.

I join to the group of Mr. Drew Lesso: AUDITING REVIEW. I cannot attend every day, but I do play the Video later when they are ready (Night).

The only feedback I have is "the lesson were recorded by Laila too fast". I cannot keep up watching, listening and taken notes. The Matematica syntax expression just fly by my 'eyes' and there is no pause to digest point by point. Yes! I always take notes since it is my way of remembering lectures/materials for the short memory retention: Hands to Brain. For Long memory, is the second round of playing the entire 1hr review video, thinking, and analyzing.

I am aware different folks have different ways of assimilating contents, just that Math and Engineering requires a different pace, and breaks (slow down). This is why in most engineering courses are arranged twice a week, max 1:15hr with breaks and jocks in the class to relaxe students.

I decide to post this feedback in case there are others like me, just wait do what you can but continue attending the program. For the Folks desperate to get into DSP, hold on. Every day has an objective to review the fundamental in Signal and systems.

Hi John, That is correct. For each lesson (except for L01) you will have a set of exercises, shared after the session is completed.

Thanks, John! Glad to hear that.

Hi Wilfredo, We will have review sessions on Fridays, if you can attend.

Hi John, my favorite by far is Oppenheim’s Signals and Systems textbook. While there are a couple of other that are good, you can’t go wrong with his version.

Hello Mariusz Do you have suggestions for reference materials such as books, online, etc? Thank you, John

Hi, I registered late for this study group and have trouble findin the links to the notebooks materials. Could you please repost those? Many thanks!

Rui