From picone at ece.msstate.edu Tue Nov 4 19:53:33 2008 From: picone at ece.msstate.edu (picone@ece.msstate.edu) Date: Tue Nov 4 19:53:43 2008 Subject: [ece3163] HW # 4.4g - from the exam Message-ID: <1225850013.4910fc9de522a@webmail.msstate.edu> I think my email to the class alias has been getting blocked lately... -Joe -------- Original Message -------- Subject: HW # 4.4g - from the exam Date: Tue, 04 Nov 2008 19:18:18 -0600 From: Joseph Picone Reply-To: joseph.picone@gmail.com To: ece3163@ece.msstate.edu Thanks to Suhyun Lim for providing a very nice solution to the exam/homework problem: http://www.ece.msstate.edu/research/isip/publications/courses/ece_3163/homework/current/hw_04_4.4g.pptx Please review this solution since a number of you wrote parts of it, but did not adequately explain where some of your key steps came from. Let me know if you have any questions. -Joe From picone at ece.msstate.edu Tue Nov 4 20:13:01 2008 From: picone at ece.msstate.edu (picone@ece.msstate.edu) Date: Tue Nov 4 20:13:12 2008 Subject: [ece3163] not sure if this went out... Message-ID: <1225851181.4911012d08b11@webmail.msstate.edu> -------- Original Message -------- Subject: Tacoma Narrows Bridge Date: Thu, 30 Oct 2008 15:01:13 -0600 From: Joseph Picone Reply-To: joseph.picone@gmail.com To: ece3163@ece.msstate.edu If you aren't familiar with this story, which we discussed anecdotally in class, there are a lot of documents on the web that describe the history and engineering issues (Google Tacoma Narrows Bridge). Here is a mesmerizing short video showing the collapse of the bridge: http://www.youtube.com/watch?v=P0Fi1VcbpAI What I would like to know is what made the driver of that car think it was safe to drive across a bridge in such an unstable condition? So hopefully you will forever think about resonant frequencies of Dr. Winton's famous circuits in a new light :) Enjoy, -Joe From picone at ece.msstate.edu Tue Nov 4 21:18:22 2008 From: picone at ece.msstate.edu (picone@ece.msstate.edu) Date: Tue Nov 4 21:18:36 2008 Subject: [ece3163] homework solutions for HW #7 Message-ID: <1225855102.4911107e30abb@webmail.msstate.edu> The solutions have been posted. I delayed this a little so I could see how a recitation section went without the students having the solutions ahead of time. Hopefully, that made the session more interactive. I'll post Chap. 8 homework solutions on Thursday. -Joe From picone at ece.msstate.edu Wed Nov 5 07:00:08 2008 From: picone at ece.msstate.edu (picone@ece.msstate.edu) Date: Wed Nov 5 07:00:24 2008 Subject: [ece3163] electromagnetic spectrum Message-ID: <1225890008.491198d847d3e@webmail.msstate.edu> Recall we were discussing this in class early in the semester. The FCC has decided to open a large chunk of the electromagnetic spectrum: http://www.businessweek.com/technology/content/nov2008/tc2008115_197440.htm?chan=top+news_top+news+index+-+temp_news+%2B+analysis This will hopefully enable a new generation of wireless services. -Joe From picone at ece.msstate.edu Thu Nov 6 14:26:20 2008 From: picone at ece.msstate.edu (Joseph Picone) Date: Thu Nov 6 14:27:22 2008 Subject: [ece3163] hw 08 Message-ID: <491352EC.7070709@ece.msstate.edu> The solutions for HW 08 have been posted. -Joe From picone at ece.msstate.edu Mon Nov 10 07:29:12 2008 From: picone at ece.msstate.edu (Joseph Picone) Date: Mon Nov 10 07:30:06 2008 Subject: [ece3163] non-compete clauses Message-ID: <49183728.1060403@ece.msstate.edu> From time to time we discuss contemporary issues in class. Here is one such issue. Many of you will have to sign what are called non-compete clauses when you start your first job. This will be buried in a stack of paperwork that your new employer wants you to sign during orientation. If you are not familiar with a non-compete form, look here: http://en.wikipedia.org/wiki/Non-compete_clause Such forms need to be given some thought, particularly if your potential new employer is asking for a lot of control over your future employment. There is an interesting battle looming between IBM and Apple on this very issue: http://blogs.zdnet.com/BTL/?p=10748 It seems to me like IBM is overstepping its bounds on this, but this will most likely have to be decided in court. My guess is either way they are trying to punish their former employee. I have seen some very nasty fights over these types of things, including lawsuits where you would potentially have to pay your former employee damages for leaving your job for a "competitor." So before you sign one of these, you should read the document carefully and perhaps have a lawyer take a look at it. -Joe From picone at ece.msstate.edu Mon Nov 10 09:22:36 2008 From: picone at ece.msstate.edu (Joseph Picone) Date: Mon Nov 10 09:23:20 2008 Subject: [ece3163] hw #9 Message-ID: <491851BC.9030703@ece.msstate.edu> A small homework assignment on the significant parts of Chapter 9 has been posted. -Joe From picone at ece.msstate.edu Sat Nov 15 21:48:29 2008 From: picone at ece.msstate.edu (Joseph Picone) Date: Sat Nov 15 21:47:28 2008 Subject: [ece3163] Re: Ch. 7 HW In-Reply-To: <1226787721.491f4b892d39a@webmail.msstate.edu> References: <1226787721.491f4b892d39a@webmail.msstate.edu> Message-ID: <491F980D.7010202@ece.msstate.edu> Craig, > I am having difficulties convincing myself that the solution to problem 7.31(a) > is correct. Is the correct solution: H(z)=(3z+1)/z > Good catch. It looks like there were some small errors in the solution. > Also, the identity used in the solutions of 7.4 a, b, g, h seems to be > incorrect. Should the identity be? > (cos(wn))^2 = .5 + 0.5*cos(wn/2) > Yes, this one mystifies me since the squared cosine results in a higher frequency, not a lower frequency. The corrections are here: http://www.ece.msstate.edu/research/isip/publications/courses/ece_3163/homework/current/hw_07_a.pptx With regard to the second issue, that seems to carry through the problem since the author relies in the result for (a) in other parts. Keep up the good work! -Joe From picone at ece.msstate.edu Mon Nov 17 18:45:41 2008 From: picone at ece.msstate.edu (Joseph Picone) Date: Mon Nov 17 18:44:39 2008 Subject: [ece3163] lecture 38 Message-ID: <49221035.9020002@ece.msstate.edu> The updated slides for lecture 38 have been posted. What should you have gotten out of today's lecture? The main point was to be able to set up the state equations. If I gave you a series circuit with R's, L's, and C's, I would hope you could write the equations by establishing state variables for each L and C. You would impress me if you could write the state equations for a more complex circuit, such as one containing series and parallel connections. Of course, there are software tools that can generate these descriptions automatically. This is essentially what is done in programs such as SPICE. You draw a circuit in a schematic capture tool, hit a button, and there you have it... If only exams were this easy :) -Joe From picone at ece.msstate.edu Mon Nov 17 21:24:04 2008 From: picone at ece.msstate.edu (Joseph Picone) Date: Mon Nov 17 21:23:07 2008 Subject: [ece3163] Re: HW-Ch 7 #36 In-Reply-To: References: <1226787721.491f4b892d39a@webmail.msstate.edu> <491F980D.7010202@ece.msstate.edu> Message-ID: <49223554.4000307@ece.msstate.edu> Will, > On part (a) should the denominator of H(z)=(z+1)*(z+1)? If not, why? > You are correct. It looks like either there was a typo in the textbook or the person providing the solution thought the second system had a denominator of (z+2). Either you can change the second system to z+2 and follow the solution, or leave it as z+1 and work up a new solution. If someone does the latter, it would be nice to publish the results to the class. Note that there are more errors as we get further into the textbook. That is going to make the third exam a little more interesting ;) Thanks, -Joe From picone at ece.msstate.edu Wed Nov 19 09:08:31 2008 From: picone at ece.msstate.edu (Joseph Picone) Date: Wed Nov 19 09:07:19 2008 Subject: [ece3163] hw #10 solutions Message-ID: <49242BEF.3030704@ece.msstate.edu> have been posted. -Joe From picone at ece.msstate.edu Thu Nov 20 17:44:00 2008 From: picone at ece.msstate.edu (Joseph Picone) Date: Thu Nov 20 17:42:50 2008 Subject: [ece3163] Re: CH7 #31 corrected soultion In-Reply-To: References: Message-ID: <4925F640.2070907@ece.msstate.edu> Jonathan, > I was looking back at the solution you posted as a correction to our other > solutions. Should the first equation be > z Q1(z) = -4 Q2(z) + X(z) ....the difference being the -4 versus +4 > If not, what am I looking at wrong? > Another good correction. You are correct. I updated the online solution. It didn't change things much because Q2() is still zero. Thanks for pointing this out, -Joe From picone at ece.msstate.edu Thu Nov 20 17:50:01 2008 From: picone at ece.msstate.edu (Joseph Picone) Date: Thu Nov 20 17:48:56 2008 Subject: [ece3163] Re: HW-Ch 9 #8 In-Reply-To: References: <1226787721.491f4b892d39a@webmail.msstate.edu> <491F980D.7010202@ece.msstate.edu> <49223554.4000307@ece.msstate.edu> Message-ID: <4925F7A9.20501@ece.msstate.edu> > On part (b) how do u get the value of s to plug into [Gc(s)*Gp(s)] so > that you can find the value of k? > This solution uses the Routh array. Since the first two coefficients are positive (1 and 15). Hence, if the third coefficient is negative, there is a sign change, which means there is one RHP pole and the system will be unstable. That (770-K)/15 < 0, or 0 <= K <= 700. You could also argue that K + 40 < 0, or K < -40, but K is restricted to be positive since technically it is a gain term. Does that help? -Joe From picone at ece.msstate.edu Thu Nov 20 19:47:00 2008 From: picone at ece.msstate.edu (Joseph Picone) Date: Thu Nov 20 19:45:55 2008 Subject: [ece3163-01] [ece3163] Re: HW-Ch 9 #8 In-Reply-To: References: <1226787721.491f4b892d39a@webmail.msstate.edu> <491F980D.7010202@ece.msstate.edu> <49223554.4000307@ece.msstate.edu> <4925F7A9.20501@ece.msstate.edu> Message-ID: <49261314.7000501@ece.msstate.edu> > I believe you are referring to the solution to part a. I was curious > about part b, finding the value of K that gives a critically damped > response. This is a point we glossed over in class. It is also not covered well in the textbook. The root locus for parts (a) and (b) can be found here: http://www.ece.msstate.edu/research/isip/publications/courses/ece_3163/homework/current/hw_09_a.pptx You can also observe these in problem 9.7. You will notice on the second plot that the point s = -2.35 is where the locus leaves the negative real axis. This means for that corresponding value of K, the poles of the feedback system have become complex, which means it is oscillating. Therefore, where the root locus crosses the negative real access can be considered the point where it is critically damped (between being underdamped, or oscillating, and overdamped, exponentially rising step response). > In the solutions it seems that you set [Gc(s)*Gp(s)] =1 and solve for > K but, how do you know what value to use for s? So this intercept is how the value of s was determined. The corresponding value of K can also be viewed as the value of K where 1 + Gc(s)Gp(s) = 0 (making this value of s a pole), or Gc(s)Gp(s) = -1. In this case that is K = 17. Of course, you would know this by plotting the root locus as well. -Joe From picone at ece.msstate.edu Fri Nov 21 08:48:23 2008 From: picone at ece.msstate.edu (Joseph Picone) Date: Fri Nov 21 08:47:15 2008 Subject: [ece3163] last hw assignment Message-ID: <4926CA37.3050906@ece.msstate.edu> I have posted a short homework assignment on Chap. 11. Given you will have access to MATLAB on the final, I guess I could give you a monster state variables problem on the final that would encapsulate everything we have learned in this course: - convert this circuit to a CT state variable description - find the transfer function - compute the output of the circuit to a given input - convert the CT system to an equivalent DT system - compute the transfer function - compare and constrast/explain the differences - implement the DT system in MATLAB - process an audio file containing the last lecture's audio - explain why the output sounds so bad ... I am looking forward to the final :) -Joe From picone at ece.msstate.edu Sun Nov 23 10:58:53 2008 From: picone at ece.msstate.edu (Joseph Picone) Date: Sun Nov 23 11:00:13 2008 Subject: [ece3163] interesting article on statistical modeling Message-ID: <49298BCD.1020202@ece.msstate.edu> As we near the end of the semester, you might be pondering "what's next? Here is an interesting article on a on-going challenge in statistical modeling promoted by Netflix: http://www.nytimes.com/2008/11/23/magazine/23Netflix-t.html?pagewanted=1&_r=1&ref=magazine This type of application is a good example of what might be considered a grand challenge problem in statistical modeling. It is also an example of how, thanks to the Internet, there are many new and interesting applications for good algorithms. Hopefully, it will make you think about the power of the tools and techniques you have learned this semester. -Joe From picone at ece.msstate.edu Sun Nov 23 13:04:18 2008 From: picone at ece.msstate.edu (Joseph Picone) Date: Sun Nov 23 13:05:09 2008 Subject: [ece3163] Re: Exam 3 In-Reply-To: <5b5367b90811230950y5750fdb0qa2f630c4e10286a7@mail.gmail.com> References: <5b5367b90811230950y5750fdb0qa2f630c4e10286a7@mail.gmail.com> Message-ID: <4929A932.4070409@ece.msstate.edu> > I overheard someone talking about chapter 6 being on the test. I thought > we had covered chapter 6 on the last exam. I have been studying over > Chapter 7,8, and 9. So I just wanted to make sure. Monday's exam covers Chaps. 7 - 9. What I said in class was that it covers the material starting with the previous exam through Chap. 9. I didn't recall exactly where the last exam left off... so that was where the confusion came from. But the syllabus had the correct starting point - 7.1. -Joe From picone at ece.msstate.edu Sun Nov 23 17:37:49 2008 From: picone at ece.msstate.edu (Joseph Picone) Date: Sun Nov 23 17:38:49 2008 Subject: [ece3163] transform tables Message-ID: <4929E94D.8040608@ece.msstate.edu> Here are scanned copies of the tables: http://www.ece.msstate.edu/research/isip/publications/courses/ece_3163/lectures/current/lecture_41_tables.pdf You can print these and bring them to the exam. I will also project them during the exam. -Joe From picone at ece.msstate.edu Mon Nov 24 11:32:14 2008 From: picone at ece.msstate.edu (Joseph Picone) Date: Mon Nov 24 11:32:43 2008 Subject: [ece3163] [Fwd: [Fwd: Re: [ECE #31249] printer in classroom]] Message-ID: <492AE51E.1070002@ece.msstate.edu> Just a gentle reminder... -Joe -------- Original Message -------- Subject: [Fwd: Re: [ECE #31249] printer in classroom] Date: Wed, 29 Oct 2008 15:46:41 -0600 From: Joseph Picone Reply-To: joseph.picone@gmail.com To: ece3163@ece.msstate.edu As I mentioned previously, for the final exam, you will be expected to use MATLAB during the exam to solve problems. This means you will be expected to write and execute MATLAB code from your laptops. To make it easy for you to turn in your results, you will need to be able to print to a printer called Blue, which will be located in the classroom. The instructions for enabling your laptop to print to Blue can be found here: http://www.ece.msstate.edu/wiki/index.php/Helpdesk#How_do_I_print_to_an_ECE_printer_from_my_personal_computer.3F Please take care of this well in advance of the final exam so that we have time to troubleshoot your problems. If you have any problems, consult with our TA, Ram, and he can help you work through these problems. Being able to print to the department printers from your laptop will be a useful capability for your future classes, so hopefully you will find this to be worth the investment in time. This is the first and only request regarding this matter that you will receive, so please add this to your To Do list. Happy printing, -Joe From rr370 at msstate.edu Tue Nov 25 14:08:32 2008 From: rr370 at msstate.edu (Ram Mohan Reddi) Date: Tue Nov 25 14:08:46 2008 Subject: [ece3163] Recitation Class cancelled Message-ID: There will be no recitation class today evening. Prepare well for the finals. Best of Luck. Enjoy the thanksgiving holidays. regards, RAM From picone at ece.msstate.edu Fri Nov 28 14:15:42 2008 From: picone at ece.msstate.edu (Joseph Picone) Date: Fri Nov 28 14:16:42 2008 Subject: [ece3163] exam no. 3 results Message-ID: <4930516E.9040804@ece.msstate.edu> Below are the results for exam no. 3 (third column). If you send me an email, I will send you your individual grade. The only problem that was not done well by some was the first problem. Some of you wrote integrals for the stability condition. For a discrete-time system, the stability condition is a summation: sum |h[n]|. Also, some of you lost a point for not explaining why the resulting sum was not bounded. The overall performance on this exam was very good. If we project this improvement in performance to the final exam, everyone should get 100 on the final ;) Let me know if you have further questions. -Joe ===================== E1 E2 E3 Avg 58 56 84 Median 61 53 93 Stdev 20 19 18 Min 20 16 45 Max 98 93 100 Histogram: < 10 0 0 0 10-19 0 1 0 20-29 1 0 0 30-39 2 3 0 40-49 4 4 1 50-59 2 4 2 60-69 7 3 2 70-79 1 3 1 80-89 2 1 4 > 90 1 1 10 Total: 20 20 20