Signals and systems class why?

Thread Starter

prophoss

Joined Feb 26, 2019
36
I am currently a student in a computer engineering degree plan. As a part of my plan we have to take signals and systems class where we learn to ... well that is the problem. I really don't know what we are learning this stuff for or what I would be using it for after college. I sort of get the math side and how to use Laplace, Fourier, and Z transforms. So far I have done well and kept a good grade point average. This class though thoroughly kicked my butt. Partly, I think, because I don't see how it all applies. I was hoping someone out there might shed some light on the application of this subject on the job site. I look forward to hearing from y'all, and thanks in advance.
 

Papabravo

Joined Feb 24, 2006
14,674
Signals and systems is about how information is represented, transferred, replicated, and analyzed. You have to be a little slow on the uptake to not see the connection to computer engineering. It is hardly appropriate for you to decide at this point what is and is not relevant to your future. You can't predict it and neither can we. Take it for granted that there are certain fundamental concepts that represent the price of admission. I never thought that metallurgical engineering and the Iron-Carbon phase diagram would be useful to me, but I was wrong. One of my first jobs was a process control system in a steel mill.
 

MrChips

Joined Oct 2, 2009
22,089
Laplace, Fourier, Z-transforms are fundamental and just a sample of transforms used in many aspects of radio, electronics, control, and computer engineering. Stick with it and you will be thankful for it one of these days.
 

crutschow

Joined Mar 14, 2008
25,653
Just because your are taking computer engineering doesn't mean you will always deal only with computers in your career.
Suppose you work for a small company that wants you to interface a computer or microprocessor to some sort of analog signals.
That's when you'll be happy you took a course in Signals and Systems.
If you wanted to deal only with computers than a more appropriate major would likely be Computer Science, not Computer Engineering.
 

Thread Starter

prophoss

Joined Feb 26, 2019
36
You have to be a little slow on the uptake to not see the connection to computer engineering.
I do not believe I am slow on the uptake but rather don't understand the application of what I am learning. That is what I am trying to get to. Your later point was valid and I am sure I will see the use in the future. The problem I am having now is trying to apply it to what I already know. I get how RLC circuits work and creating a filter using them. Or how a digital response might act in a step function. No sir I do see how it could apply I am just having a hard time applying it.
 

Papabravo

Joined Feb 24, 2006
14,674
I do not believe I am slow on the uptake but rather don't understand the application of what I am learning. That is what I am trying to get to. Your later point was valid and I am sure I will see the use in the future. The problem I am having now is trying to apply it to what I already know. I get how RLC circuits work and creating a filter using them. Or how a digital response might act in a step function. No sir I do see how it could apply I am just having a hard time applying it.
You're entitled to you own opinion, but you're not necessarily entitled to your own facts. Have some patience. It will take 4 plus years from beginning to end to get your degree. I would say that it might be 10 years and two or three jobs into your career before you can fit the pieces together. You should not worry about fitting the pieces together, but rather be laser focused on knowing the material like the back of your hand. The better you know the basic material, the easier the later courses will be, and the more confident you will be in the interview and your interactions with your peers and colleagues. I really don't get why you think it is important to put the pieces together before you even know what the pieces are.
 

MrChips

Joined Oct 2, 2009
22,089
Right this moment I am heavily involved with a computer engineering application to measure engine vibration.
Guess what I have to program right now - Fourier transformation on a microcontroller!
 

Thread Starter

prophoss

Joined Feb 26, 2019
36
You're entitled to you own opinion, but you're not necessarily entitled to your own facts. Have some patience. It will take 4 plus years from beginning to end to get your degree. I would say that it might be 10 years and two or three jobs into your career before you can fit the pieces together. You should not worry about fitting the pieces together, but rather be laser focused on knowing the material like the back of your hand. The better you know the basic material, the easier the later courses will be, and the more confident you will be in the interview and your interactions with your peers and colleagues. I really don't get why you think it is important to put the pieces together before you even know what the pieces are.
That makes more sense to me, and you are correct. I am entitled to my own opinion right or wrong! ;)
I think that actually may have been my biggest problem with this class. I got caught up with the math and sort of missed the point. Easy for me to do because I like dealing with numbers not necessarily ideas. I am a very hands on person so I like to put a piece of code or hardware to work and see what it does rather than read about theory. I think I am starting to understand where this is going now. Thank you.
 

TechWise

Joined Aug 24, 2018
134
I see where @prophoss is coming from. We did a "Digital Systems" class in second year which was all about designing combinational logic circuits. There were loads of practical examples throughout and we had assignments where we designed digital logic for vending machines and that sort of thing. It made a lot of sense to me and most people did well in that class.

In third year, the successor to the digital class was "Signals and Systems". First semester was all in the continuous domain and mostly dealing with Laplace transforms. The class was entirely mathematical and absolutely no effort was made to link it to anything practical. We weren't even presented with something as simple as an RC circuit, so most people struggled to see what the point of all this was. People's minds were totally blown in the machine's class the following year when the lecturer used a Laplace transform to solve a mechanical differential equation, but like I said, zero effort was made to show any practical use for the stuff we were learning in the Signals and Systems class. The second semester was entirely in the discrete domain, so mostly z transforms and manipulations. Control systems were not taught until the following year, so again, no one really understood what on earth this was all for. We also spent weeks and weeks on direct forms and diagrams that no one really saw the point of.

The z-transform only started to make sense to me recently when I started to convert simple PI controllers to the z-domain then into a difference equation and implementing them in C-code. The direct form stuff only started to make sense when I started implementing digital butterworth filters on a microcontroller and I had to decide how to do it. Once you start looking at these practical implementations, you see why moving from one direct form to another can be useful to get rid of a multiplication or reduce the register count, but none of that was ever mentioned at the time.
 

Thread Starter

prophoss

Joined Feb 26, 2019
36
I see where @prophoss is coming from. We did a "Digital Systems" class in second year which was all about designing combinational logic circuits. There were loads of practical examples throughout and we had assignments where we designed digital logic for vending machines and that sort of thing. It made a lot of sense to me and most people did well in that class.

In third year, the successor to the digital class was "Signals and Systems". First semester was all in the continuous domain and mostly dealing with Laplace transforms. The class was entirely mathematical and absolutely no effort was made to link it to anything practical. We weren't even presented with something as simple as an RC circuit, so most people struggled to see what the point of all this was. People's minds were totally blown in the machine's class the following year when the lecturer used a Laplace transform to solve a mechanical differential equation, but like I said, zero effort was made to show any practical use for the stuff we were learning in the Signals and Systems class. The second semester was entirely in the discrete domain, so mostly z transforms and manipulations. Control systems were not taught until the following year, so again, no one really understood what on earth this was all for. We also spent weeks and weeks on direct forms and diagrams that no one really saw the point of.

The z-transform only started to make sense to me recently when I started to convert simple PI controllers to the z-domain then into a difference equation and implementing them in C-code. The direct form stuff only started to make sense when I started implementing digital butterworth filters on a microcontroller and I had to decide how to do it. Once you start looking at these practical implementations, you see why moving from one direct form to another can be useful to get rid of a multiplication or reduce the register count, but none of that was ever mentioned at the time.
Exactly, and that drives me nuts.
 

Papabravo

Joined Feb 24, 2006
14,674
Maybe it is just a lack of confidence in the people who put the curriculum together. If something doesn't correspond to your sense of what is relevant it is easier to throw stones and whine that it is irrelevant, or too hard, or not connected with anything I understand. What a bunch or r/Entitled Kids. Since the time of Newton we have struggled with the teaching of Science and Mathematics. How about a soupçon of confidence that there is an underlying purpose there that the process will reveal.
 

TechWise

Joined Aug 24, 2018
134
Maybe it is just a lack of confidence in the people who put the curriculum together. If something doesn't correspond to your sense of what is relevant it is easier to throw stones and whine that it is irrelevant, or too hard, or not connected with anything I understand. What a bunch or r/Entitled Kids. Since the time of Newton we have struggled with the teaching of Science and Mathematics. How about a soupçon of confidence that there is an underlying purpose there that the process will reveal.
I'm not sure why you feel the need to belittle people with less knowledge than yourself @Papabravo. You've done it to me previously, I've observed you doing it to others and now, only three messages into a brand new thread, you're accusing a new forum member of being "slow on the uptake" and you're accusing me of being an "Entitled Kid".

Of course, there are elements of theory that are quite abstract. There are also situations where you need to grind through a lot of mathematics before you can start to look at the application. There's simply no excuse though for having entire classes where students come out the other end wondering what the hell it was all for. We are engineers after all, not mathematicians or theoretical physicists. Employers in industry want engineers who can solve real problems, not recite wrote learned formulae or work out the inverse laplace transform of a tenth order transfer function with pencil and paper.

There's no excuse for having a two-semester Power Systems class where the students solve power flow problems by hand using an iterative Newton method and six sides of paper then come out the other end not knowing what a circuit breaker is. That's how we were taught power systems. There's no excuse for having a Signals and Systems class where students sit and convolve a big rectangle with a little rectangle on paper then come out not knowing what an ADC is. That's how we were taught about Systems. There's no excuse for having an Analogue Electronics class where the students work out the transfer function of a 15 input summing amplifier, using four sides of paper then come out not knowing what a bypass capacitor is. That's how we were taught Analogue Circuits.
 

Papabravo

Joined Feb 24, 2006
14,674
I'm not sure why you feel the need to belittle people with less knowledge than yourself @Papabravo. You've done it to me previously, I've observed you doing it to others and now, only three messages into a brand new thread, you're accusing a new forum member of being "slow on the uptake" and you're accusing me of being an "Entitled Kid".

Of course, there are elements of theory that are quite abstract. There are also situations where you need to grind through a lot of mathematics before you can start to look at the application. There's simply no excuse though for having entire classes where students come out the other end wondering what the hell it was all for. We are engineers after all, not mathematicians or theoretical physicists. Employers in industry want engineers who can solve real problems, not recite wrote learned formulae or work out the inverse laplace transform of a tenth order transfer function with pencil and paper.

There's no excuse for having a two-semester Power Systems class where the students solve power flow problems by hand using an iterative Newton method and six sides of paper then come out the other end not knowing what a circuit breaker is. That's how we were taught power systems. There's no excuse for having a Signals and Systems class where students sit and convolve a big rectangle with a little rectangle on paper then come out not knowing what an ADC is. That's how we were taught about Systems. There's no excuse for having an Analogue Electronics class where the students work out the transfer function of a 15 input summing amplifier, using four sides of paper then come out not knowing what a bypass capacitor is. That's how we were taught Analogue Circuits.
And we should put y'all in charge because you are so much wiser about how education should work. If you're going to b***h about something you should expect pushback. This is a furum, not a place where everybody gets an award for participation.
 

Delta prime

Joined Nov 15, 2019
576
Many students complain that they have to study subjects which are not relevant to their interests or ambitions. I am the only exception to this because the majority of my professors were knockouts.
 

Papabravo

Joined Feb 24, 2006
14,674
Many students complain that they have to study subjects which are not relevant to their interests or ambitions. I am the only exception to this because the majority of my professors were knockouts.
Even bad professors cannot impede great students. Having the right attitude going in helps a great deal.
I could have complained about solving problems in thermodynamics using Steam Tables, but I didn't. We also had to use slide rules and four place log tables to do calculations and a cheap computer with no peripherals was over $10,000 (a PDP-8). No complaints there either.
 

bogosort

Joined Sep 24, 2011
519
There's simply no excuse though for having entire classes where students come out the other end wondering what the hell it was all for.
I sympathize with the OP and the many other students with similar experiences. Signals and Systems, in particular, seems to have a chicken-and-egg problem, Put plainly, most students do not have the experience to appreciate the enormous value in developing a language and theory to quantitatively characterize information and information processing. But to get that experience and appreciation, one typically has to work through a sufficient number of real-world engineering problems, almost all of which require some proficiency in the language and theory of information processing.

In short, students have to slog through Signals and Systems in order to be able to work on the problems that will give them the appreciation for having studied Signals and Systems. (I've had many colleagues tell me that they wished they had tackled Signals and Systems more seriously.) This is compounded by the fact that, like most STEM courses, the Signals and Systems curriculum is non-negotiable and the instructor has to ensure that all of the topics are covered. Lingering on any one topic -- no matter how critical to future success -- is strongly disincentivized. A good instructor will know how to ground the abstract material with punchy, real-world examples, but they'll rarely be afforded the time to ensure that the class as a whole has the proper big-picture view.

Of course, these types of situations are where exceptionally motivated and mathematically mature students can really stand out. But for most students at most schools, I believe that STEM coursework is far from optimal with respect to producing well-educated, critical-thinking engineers. Rote calculation is by far the least important aspect of any course, especially Signals and Systems, yet that is almost invariably the entire focus. Calculation should be an aid to understanding, not the goal. Unfortunately, this is a systematic problem as engineering prerequisites are often based on what calculations the students can be expected to perform. It's much easier to propose, have approved, and then teach the standard curriculum than it is to develop a novel approach that both gives the students the true flavor of the subject and ensures that they can do the myriad Laplace transforms that their Control Systems class will require of them.
 

Papabravo

Joined Feb 24, 2006
14,674
Not everybody is cut out for the dedication and discipline of engineering. As I see it the major problem is engaging in slow sequential failure. If it is not your cup of tea get out in the early stages before you waste time and resources pursuing a goal you cannot reach. The number one rule of entrepreneurs is: "don't compound your mistakes by continuing to make them expecting a different result."
 
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