Analog engineering, worth it? - Page 1
Forum section: electronics / general

author: Enron
author_rank: Contributor
timestamp: August 21, 2012, 10:31:23 pm
content: I know there will always be IC fabrication, but what about analog circuits as a whole?I'm not a big programming fan, but I like to play with audio circuits. I am just wonderingif there is anything really besides audio/radio circuits, that will still be valuable to learn, ifdone using analog?I ask because I want to move on to something else besides audio, but don't want toprogram. I want to look into LED light fixtures, but we all know how many times we had tomake a LED light up in class...

author: Baliszoft
author_rank: Frequent Contributor
timestamp: August 21, 2012, 11:23:53 pm
content: Do some research in analog filters. They also come handy when it is about doing AD conversion (before digital signal processing).

author: EEVblog
author_rank: Unknown
timestamp: August 21, 2012, 11:51:38 pm
content: Quote from: Enron on August 21, 2012, 10:31:23 pmTons of stuff.Precision sensor amplifiers (wheatstone bridge for example), filters, PLL's, integrators, power supplies, to name but a few.Dave.

author: Enron
author_rank: Contributor
timestamp: August 21, 2012, 11:52:34 pm
content: I suppose I could work on a project that I always wanted to do. I wanted to do a frequency multiplier, with a guitar through a pedal. I was going to go about that with some kind of analog PLL setup, but maybe I can go ahead and try DSP.

author: Enron
author_rank: Contributor
timestamp: August 22, 2012, 12:37:37 am
content: Thanks for some ideas guys! Back to the lab.

author: Rerouter
author_rank: Super Contributor
timestamp: August 22, 2012, 02:34:41 am
content: there is also op amps covered in analog engineering, and they are quite a large chunk of most analog systems, and while they seem simple enough there are hundreds of little traps about them, from offset voltages to common mode ranges, and others,i myself enjoy the feedback loops side of analog engineering, like using a dozen op amps, with 5 inputs and 3 outputs to make a stable and inter-related control system where all the corrections and actions are done in a very fast analog loop with no need for digital intervention other than feeding in set points and reading off values for operator convenience,then there are tricks you otherwise might never learn without the variety, like why your 0.1uF capacitor across your logic chips supply rails was not a good choice and causes problems, or why your adc's 10K input resistance is skewing your readings,

author: MetraCollector
author_rank: Regular Contributor
timestamp: August 22, 2012, 08:51:01 am
content: You do not have to worry.I work for ON Semiconductor automotive division as a student in test engineering and there are many workplaces here.Analog designers are the most respected and desirable engineers. They have usually highest salaries.Despite it is about IC designing, they have to design filters, voltage converters or design test benches and many other activities.Gigahertz bands are not usually suitable for digital processing, so it is essential not to forget about analog design

author: thb
author_rank: Newbie
timestamp: August 22, 2012, 02:40:30 pm
content: Analog: work is fun, result is boring.Digital: work is boring, result is cool.

author: Neilm
author_rank: Super Contributor
timestamp: August 22, 2012, 07:07:42 pm
content: If you think about most of the test equipment you can think of will use analogue engineering. The front end of an oscilloscope, the input on you multimeter, the input of logic analysers, Dave's ucurrent the list goes on.I work for a company that makes very sensitive test equipment. It is impossible to measure femto-amps without some very good engineering. We keep finding that recruiting engineers that can do digital is easy. Getting someone who is very good at analogue electronics is hard. Last time we looked we went for 18 months and still didn't get what we wanted.YoursNeil

author: AndyC_772
author_rank: Super Contributor
timestamp: August 22, 2012, 08:15:01 pm
content: Quote from: thb on August 22, 2012, 02:40:30 pmAt anything faster than trivial speeds, digital electronics *is* analogue

author: Simon
author_rank: Unknown
timestamp: August 22, 2012, 09:38:12 pm
content: Quote from: AndyC_772 on August 22, 2012, 08:15:01 pmVery true, digital is but an abstraction of the real world with rules that keeps you in its controlled boundaries which were determined by analog in the first place.Digital is therefor easier and so often preceded as many can program too now.I think soon finding people good in analog will be like trying to find a web developer to write in code versus one that just installs WordPress.

author: Enron
author_rank: Contributor
timestamp: August 22, 2012, 10:59:35 pm
content: Thanks for all the replies!You guys mentioned some great stuff, to keep me motivated in analog design.I'm going to explore some things that where mentioned, build them, and keepadding to my portfolio.IC design may still be an option. I just never gave it much thought.

author: AndyC_772
author_rank: Super Contributor
timestamp: August 23, 2012, 07:09:49 am
content: Quote from: Simon on August 22, 2012, 09:38:12 pmEver implemented a DDR2 or DDR3 memory interface, or anything else that relies on correctly matching a high speed transmission line? The days of digital being just ones and zeroes ended a long time ago...

author: StubbornGreek
author_rank: Frequent Contributor
timestamp: August 23, 2012, 01:52:52 pm
content: Quote from: AndyC_772 on August 23, 2012, 07:09:49 amSorry but can't help being a bit of a smart-ass here; it still comes down to the 1's and 0's, just like the words 'yes' and 'thermodynamics' use the same alphabet - one is more complex than the other but they use the same building blocks.Analogue circuitry is the backbone of all electronics (IMHO).

author: saturation
author_rank: Super Contributor
timestamp: August 23, 2012, 05:12:19 pm
content: From an electronics level, all of the natural world speaks analog, so long as you interface with it, take data from or talk back to it, it will require the concepts of analog.

author: AndyC_772
author_rank: Super Contributor
timestamp: August 23, 2012, 06:17:44 pm
content: Quote from: StubbornGreek on August 23, 2012, 01:52:52 pmWith due respect, I think you've just answered my question beautifully. The answer is clearly 'no', you've not implemented such an interface yourself.If you had, then you'd know all about setup and hold timings (analogue), noise margin (analogue), slew rate (analogue), clock jitter (analogue), duty cycle asymmetry (analogue), termination voltage (analogue), monotonicity (analogue), supply voltage (analogue), termination impedance (analogue), length matching (analogue), crosstalk (analogue), propagation delay (analogue), and the way all those things vary with time, from device to device, and with temperature - all analogue.The fact that your PC's memory *looks* like a digital system from the outside, and does in fact allow you to store and retrieve ones and zeroes reliably, is a remarkable feat of analogue design.If you have any doubts at all that it's an analogue design problem, do dig out any CPU manufacturer's application notes on how to lay out a DDR2 or DDR3 PCB. It's quite the eye-opener.

author: jahonen
author_rank: Super Contributor
timestamp: August 23, 2012, 06:57:12 pm
content: Yep, successful SI design requires understanding of analog stuff. And also let's not forget about one very important aspect of a product design today, EMC. Failing to meet EMC requirements can cause detrimental loss for the company. Sooner the requirements are met with minimal cost, the better. Good EMC design is all about understanding analog properties of the signals (and some RF concepts which "real" RF designers have had to live with from day zero).I have used to think that digital is just non-linear high-bandwidth analog stuff, purely digital system exists only in daydreams of mathematician. One good example is to connect a series of gates to a high-frequency clock signal, and when enough gates have been added, the signal just ceases to exist due to the skew accumulation (analog property of logic gates), although from purely digital view, there should be no problemRegards,Janne

author: Simon
author_rank: Unknown
timestamp: August 23, 2012, 07:24:39 pm
content: Quote from: AndyC_772 on August 23, 2012, 07:09:49 amOK I over simplified and was referring to lower speed stuff like micro's, a previous post had already pointed out that high speed digital is effectively analog.Example, if your running a motor with 1 KHz PWM most mosfets will be fast enough and you can practically assume the output as square. But go into 100's of MHz and rise and fall times are considered and the fact that the output is somewhat square is acknowledged.

author: StubbornGreek
author_rank: Frequent Contributor
timestamp: August 24, 2012, 12:38:59 am
content: With the same due respect, I don't understand your point (honestly). I have an understanding of skew, jitter, termination voltage, etc., etc. Also, I don't contest that implementing DDR2 (or 3) requires knowledge and talent. I was simply stating that digital will always amount to 1's and 0's, no matter how complex the overall design becomes.As far as analogue electronics are concerned, the digital world doesn't even exist without it.Quote from: AndyC_772 on August 23, 2012, 06:17:44 pm

author: EEVblog
author_rank: Unknown
timestamp: August 24, 2012, 01:16:42 am
content: Quote from: AndyC_772 on August 23, 2012, 07:09:49 amDigital is one and zero by definition, and always will beThere are two separate issues here. One is designing and implementing a system to allow it to work in a digital way. And then so long as you operate the system within the designed margins for digital operation, it then switches from being an "analog" system to a "digital" system. So in theory "digital designers" do not need to be concerned with the analog world, because someone with analog knowledge (who is not necessarily an analog design specialist) has designed that system to work for them.But in practice, for that to be the case, you are no longer a "digital designer" but simply a "programmer". And programmers rightly should have no concern with the analog world.There is no way anyone would call someone laying out a PCB, let alone high speed DDR, a "digital designer". You need at least rudimentary analog knowledge to lay out almost any PCB properly. A modern high speed DDR layout does not require a specialist analog design engineer though, but it does require a designer with enough basic knowledge of analog to understand things.There have always been issues with designing digital systems, it's not just about speed.For example, the early (non CMOS) digital systems had fanout current drive issues, even operating at 1Hz.Similar issues still exist for example with FPGA "digital designers". You can't just use the one clock into your FPGA to drive unlimited numbers of internal gates in unlimited locations across the chip.Basically, it's impossible to do any electronics design without a basic foundation of analog.But one does not need to be an analog specialist for the majority of electronics design these days, but there are still a ton of niches were analog specialists are essential.Dave.

author: AndyC_772
author_rank: Super Contributor
timestamp: August 24, 2012, 06:22:41 am
content: Quote from: StubbornGreek on August 24, 2012, 12:38:59 amAll I'm getting at is that most of the issues a designer faces when implementing a very fast interface like this aren't what you might associate with 'traditional' digital design. The memory interface in a product like a modern PC is switching at UHF frequencies, getting on towards microwave - and so the design process would be more familiar to a radio engineer than to someone brought up writing software or building slower digital circuits that just flip between 1 and 0.The signals don't simply switch between high and low; they spend most of their time in a transitional period between the two. Nor are they simply driven from one device and received by another - they start at one device but then propagate across the PCB, changing shape, reflecting and interfering with themselves and each other as the wave makes its way to the receiver.Read the data sheet for a modern memory IC and you might be led to believe it's a digital device. It's specified in terms of its logic 0 and logic 1 voltages, setup and hold times, access delays, minimum pulse widths and so on. But in order to actually meet those specifications, the design engineer can no longer just add up the delays and check there's still some margin at the receiver - it's not that easy any more!I had a quick look around for images to show the actual signals on a DDR interface, but unfortunately most of Google's image results show working interfaces which have been implemented correctly, and the signals really do resemble 'traditional' 1-and-0 digital plots. But I did find this one:...which sure looks like an analogue signal to me.

author: AndyC_772
author_rank: Super Contributor
timestamp: August 24, 2012, 06:28:45 am
content: Quote from: EEVblog on August 24, 2012, 01:16:42 amThe Altera Cyclone series FPGAs that I've been using for years have dedicated global, high fan-out, low skew clock trees implemented on the silicon for just this purpose; the synthesis tool should spot global clocks and assign them to these clock trees automatically. I'm sure other vendors have the same, they're invaluable.I agree that if you run out of these global nets, the clock has to go via regular logic instead, and the skew soon adds up to a design with a very slow Fmax.

author: rolycat
author_rank: Super Contributor
timestamp: August 24, 2012, 01:34:01 pm
content: Quote from: EEVblog on August 24, 2012, 01:16:42 amQuite apart from any analogue design considerations, this is incorrect.Binaryis composed of ones and zeros by definition, butdigitalcan mean any set of discrete values.Even at the lowest level, balanced ternary (1, 0 and -1) computers have been built and may in the future replace binary systems. For example, ternary representations could prove more efficient in optical computers.

author: StubbornGreek
author_rank: Frequent Contributor
timestamp: August 24, 2012, 09:48:26 pm
content: Quote from: AndyC_772 on August 24, 2012, 06:22:41 amI pretty much agree and see what you're saying but again the end result is either a 1 or a 0 (intermediate states aside).

author: StubbornGreek
author_rank: Frequent Contributor
timestamp: August 24, 2012, 09:50:11 pm
content: Quote from: rolycat on August 24, 2012, 01:34:01 pmI'm pretty sure you mean this is incorrect when considering (possible applications of) quantum computing and some Russian tech from the 50's. Personally, I'm not aware of any other applications. Are there and I'm just in the dark here?

author: rolycat
author_rank: Super Contributor
timestamp: August 25, 2012, 12:02:24 am
content: Quote from: StubbornGreek on August 24, 2012, 09:50:11 pmI'm pretty sure I don't.I mean it's incorrect when considering anything. The definition of digital does not mean just ones and zeros.QuoteThere are indeed. Consulting the Wikipedia entry on ternary computers is not sufficient research.Ternary codes are extensively used in communications, for example in fast Ethernet signalling. The ISDN basic rate interface uses quaternary encoding, with four voltage levels on the line.As another illustration, ASCII is a digital code but not a binary one. The underlying representation in current computers happens to be binary, but when ASCII is being sent between computers it may well not be.

author: Obi_Kwiet
author_rank: Regular Contributor
timestamp: August 25, 2012, 03:38:44 am
content: Quote from: StubbornGreek on August 23, 2012, 01:52:52 pmHis point is that you have to consider a lot of analog design to get it to the point where it is 1's and 0's.

author: BravoV
author_rank: Super Contributor
timestamp: August 25, 2012, 06:57:05 am
content: When every time I read this kind of debate (analog vs digital), its like watching a duel between a brain surgeon vs a psychologist on who has the bigger dick.

author: StubbornGreek
author_rank: Frequent Contributor
timestamp: August 25, 2012, 12:56:49 pm
content: Quote from: rolycat on August 25, 2012, 12:02:24 amTernary signals through ethernet are just that, signals. Digital 1's and 0's still make the operation possible and are ultimately the bottom layer. I was not aware of ternary signaling in ASCII so I can't comment until I've looked up some info.What makes you think I received my understanding of ternary computing (signaling) from wiki? Were you being funny of just out to insult?EDIT: Google isn't helping much as every article I find refers to ASCII being a binary process. Instead of trying to show everyone how smart you are through clever quips, how about educate me? Where can I find info on this?EDIT2: We are talking hardware here, right? I'm not debating digital code as there is no such thing as analogue code.

author: rolycat
author_rank: Super Contributor
timestamp: August 25, 2012, 08:05:21 pm
content: Quote from: StubbornGreek on August 25, 2012, 12:56:49 pmWhat's your point? Binary signals in a computer are 'just that' as well. Computers don't do anything without signals.QuoteThey only become the bottom layer at the endpoints, and that is to some degree a historical accident.You say "Digital 1's and 0's" as if they are the only digits that exist. What about digital 2's and 3's and 4's and so on? We all use them every day.QuoteWell, you did, didn't you?I was struck by the exact correspondence between your attempt to sum up applications of ternary notation and the wiki entry.I wasn't trying to insult you, although since your original response to my post was a little snarky it seems somewhat perverse to get offended when I respond in kind.QuoteYou must be looking at a different internet to me, since I can't find a single article which describes ASCII as a binary process. Could you supply a URL?I am not trying to show everyone how smart I am, I was simply trying to correct what appears to be a common misapprehension, namely the tendency to conflate 'digital' with 'binary', even by highly intelligent and knowledgeable individuals such as Dave. If you recall, he stated that 'Digital is one and zero by definition, and always will be'. That's both categorical and incorrect.QuoteI was using hardware illustrations since this is an electronics forum, not a programming one. The principle is universal, though.Please don't get hung up about ternary. It's just an example of the general principle that digital information can be represented using a variety of encoding mechanisms, and binary is merely one such.

author: StubbornGreek
author_rank: Frequent Contributor
timestamp: August 26, 2012, 02:40:42 am
content: Quote from: rolycat on August 25, 2012, 08:05:21 pmAs for the first three statements above, you've somewhat answered yourself. Its the end points that we're speaking of here; I can only assume the last statement to be sarcasm as I'm sure you understood 1's and 0's to mean on and off or high and low (which-have-you) - what do 2's, 3's, etc have to do with anything?To answer your question (although I do feel a bit goaded here), I first heard of ternary computing a couple of years ago (maybe '09 or '10) while reading an article on quantum computing (the possible venues of). When I did a bit more due diligence, someone was kind enough to point out that only the Soviets successfully implemented something like this but it didn't catch on and lasted less than a decade in the field. So, the fact that the Wiki article mentions the same tech (one obsolete and the other mostly theoretical) supports what exactly? I find it comical that you even checked.Also, I ask for your direction/assistance and I get sarcasm in return - um, yea, pretty sure we're on the same internet... If not intelligence, what are you trying to show? The reason everyone "conflates" (combines? confuses? brings together? - sometimes a $0.05 is worth more than a $5 word) digital with binary is because 'at the end points' digital is either on or off (high or low).Not wanting to go into a programming rant explains everything... I simply don't agree, the concepts of software and hardware are not universal. May I ask, is this what you do (work with code)?My first statement is what you seem to have an issue with but it wasn't meant to be offensive and I don't believe you responded in kind. However, I believe I'm feeding into this a bit too now so how about calling it a difference of perception?

author: PA4TIM
author_rank: Super Contributor
timestamp: August 26, 2012, 07:36:19 am
content: I do analog design ( as a hobby, to bad I found out to late electronics is what I like most because otherwise I would like to do it for a living, my knowledge is high enough I think, but no papers)But i'm confused now, if digital is about 0 or 1, or on/off , is using a comprator making me a digital designerI think there is no strickt border betweem analog and digital when we talk about the hardware design.Like working with 74LS logic is kind a digital and routing GHz digital signals is almost analog RF engineering.It does not matter what the signal is, it are all currents and voltages. I think we must more think of two types of digital designers. The first one is a programmer who is able to connect some basic hardware blocks together. ( like a uP, an LCD, a latch, some external memory, sensors or servo's that can be connected straight to the uP or through a dedicated out of the box " translate/connect" IC.The other one is basicly an analog engineer but he only works with digital signals, he knows all about bitrates, logic levels, transition times, timing troubles, seperating and filtering signals ect but most of the time he is doing hardware and not programming.I can transform an analog signal into digital, but when it is digital it stops for me. I can design the microcontroller upin there, interface it, feed it but it will stay braindead because I can not write software. For instance an measure instrument that has a uP in it. I can design the whole thing, but i have to someone my demands for the uP, he then tells me the processor usable, and if it s build i must find someone to write the software.If I was always using uP's and programming them. i would have designed a program and made hardware needed for the software. I could say I was a digital designer. Maybe ask some advise about the translation from some analog stuff in to digital.The result of both designers could result in the same instrument. Only the design viewpoint is different.

author: merlinb
author_rank: Contributor
timestamp: August 26, 2012, 09:15:05 am
content: It's merely a matter of clearing up the nomenclature- Rolycat is indulging in a bit of harmless forum pedantry. Don't get too het up on it! He's just pointing out that the word 'digital' is not synonymous with 'binary'.Binaryis simply a numbers system that has only 0s and 1s (base 2).Butdigitalis not restricted to just 0s and 1s. It can use any discrete numbers system to handle information- binary, ternary, quaternary, hex, etc. It is entirely possible to build computing circuits that use more than one discrete 'voltage level' to handle data- not just 0V and 5V (or whatever).In other words, digital is not always just 0s and 1s (but itusuallyis!)Analoguses continues values of course, no number system required.

author: rolycat
author_rank: Super Contributor
timestamp: August 26, 2012, 02:28:36 pm
content: Quote from: merlinb on August 26, 2012, 09:15:05 amIt's true! I'm a pedant and proud.I like to think, though, that it's pedagogical pedantry with a practical purpose