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Analog Angle Blog

Hey, Digital Guys: Wake Up & Smell the Analog Reality!

A brief introduction: I’ve been invited to provide regular perspectives on analog issues, design, components, and more, for Planet Analog, and I've chosen to so via this Analog Angle blog (I’d prefer to call it a “column” rather than a blog, but that’s another story, and for another time).

I am happy to do this, because I have been a part of the analog engineering and editorial world for many years.

We’ve heard the repeated refrains that “everything’s going digital” and “analog is dead/dying.” All I can say is this: “Yes” to that first statement and a loud “Heck, No” to the second one. My sense is that the second theme comes from three groups: newbie engineers who should know better, and will know better soon; software coders who have no need (yet) to know better; and “Wall Street” industry analysts who don’t know better and likely never will.

Here’s the reality of the situation, not as seen by me, but as defined by a “higher authority” — the laws of physics. There’s no avoiding that, in the broad sense, digital is a just subset of analog. Sure, that’s somewhat narcissistic, but that doesn’t mean it isn’t true.

There’s no avoiding this reality. As system clocks increase from the range of several hundred MHz to GHz and higher zones, and as data rates go from hundreds of Mbit/s to tens of Gbit/s, the technical, physical-level issues that presumed digital designers struggle with are primarily analog in nature. We’re talking signal integrity, intersymbol interference, eye patterns, wired/wireless/optical drivers and receivers, switching currents, and EMI/RFI and EMC, just for starters. These formerly modest (or even ignorable) issues now rear their analog heads and make the clean, sanitized world of ones and zeroes into a harsh environment for getting intact, error-free signals from point A to point B.

The implications for high-speed, high-performance digital circuit and system designers are pervasive. It’s not enough to do a good digital design. Any schematic “on paper” is just a start. Issues such as PC board layout, signal grounding, parasitic inductance and capacitance, and adjacent signals all affect the physical implementation of your elegant design.

For those of you who are doing relatively low-speed digital work, don’t get too relaxed: Analog hasn’t forgotten you, either. You still have to worry about current flow, return paths, ground loops, shielding, isolation, IR drop, switching, sources and loads, and timing issues.

As I talk about analog-centric topics in coming weeks and months, the underlying message I have for you is simple: Even if you’re nominally a digital designer, brush up on analog. I don’t mean you have to go back to Maxwell’s equations, but you do have to look at the eternal fundamentals of voltage, current, slewing, noise, power sourcing, grounds, thermal concerns, and temperature coefficients.

That’s where I’ll be going, and I invite you to join me on the journey.

14 comments on “Hey, Digital Guys: Wake Up & Smell the Analog Reality!

  1. bolaji.ojo
    January 11, 2013

    Hi Bill, Good to have you on this site. I can't think of any other industry observers who's able to provide the deep insight you can offer. I look forward to reading more from you on the analog world and especially the companies in the industry sector.

  2. Bill_Jaffa
    January 11, 2013

    Thanks, Bolaji–I'm looking forward to the opportunity.

  3. Michael Dunn
    January 11, 2013

    I've been calling digital a figment of the imagination for years 🙂  It's just a very simple-minded way to interpret an analog signal.

  4. Brad Albing
    January 14, 2013

    Hi Bill – you'll probably make some of the digital guys cranky with this sort of thinking. Eventually, they will come around.

  5. Bill_Jaffa
    January 14, 2013

    Cranky or not, doesn't matter to me–I'm just the messenger, reminding folks of the laws of physics here.

  6. Rodney Brown
    January 14, 2013

    If we are going to get all physics up in here, how about this: digital is particles, analog is waves, and the circuit board is the quantum world in which the signal exists as both. Might be stretching that metaphor a bit at this point though.

  7. Lee H Goldberg
    January 14, 2013

    Great to see you here Bill – And big kudos on your opening volley. It's a nice take on an old colleague's maxim “all this silly digital stuff is just a special case of analog”. Most of my engieering expereince has been with digital and embedded systems doing real-world tasks ranging from high-speed printers and early artificial vision systems to ultrasonic test equipment and have always been in awe of the guys and gals who were responsible for the analog/RF elements of my designs. Since there's a lot of analog actioon in the open-source hardware applications and some solid-state lighting projects I'm messing around with these days, it's great to find a place like this where we get the benfit of hanging with sarp analog minds.

     

    looks like Brad's well on his way to building an all-star team of analog experts. I'm thrilled bout the present cast of characters already on this site and look forward to seeing who else he's got lurking in the wings. Maybe he can even convince Paul Rako or Bonnie Baker to pop in occasiaonaly. I just wish Bob Pease and Frank Goodenough were still around to add conversation…

  8. Bill_Jaffa
    January 14, 2013

    Sorry, I can't go along with your approach and metaphor here. The particle/wave duality allows us to look at experiments and data from two legimate perspectives and live with apparent contradictions that puzzled physicists in the days before quantum physics as we now understand it. But “digital is a subset of analog” expresses a reality–they are not two equally legitimate ways of looking at signals, despite what the digital-first crowd would like us to think. One is a restricted version of the other, sort of how Newtonian physics is a “simplified” version of relativistic physics, and works–but only up to a point, under carefully defined circumstances.

    Seems like this is a good subject for a post-conference discussion at a local waterhole, IMO!

  9. Brad Albing
    January 14, 2013

    I'll poke around a bit and see if I can get Paul and Bonnie interested. It could happen…. And yes, I miss Pease. And Jim Williams. Well, we're standing on the shoulders of giants, so that'll improve the likelihood of success. I'll blog about that very soon.

  10. RJShank
    January 17, 2013

    We used to say there are only 2 digital problems, stuck at one and stuck at zero.  The rest are analog.

  11. TM123
    January 17, 2013

    Hello World! (and welcome to you Bill)

    I have been involved in Analogue stuff since the early 70s – apart from a short 30 year stint in the IT world, I am back doing Analogue stuff – and loving it!

    Even repairing old stuff has its joys – Designing new stuff is approaching heaven for me! And there's heaps of it to do…

    Unfortunately, I am in a sea of naysayers (and youngsters) who just do not get the Analogue reality – but regardless, I soldier on. I look forward to ascerbic comments and being able to contribute where I can.

     

    back to lurk mode!

  12. Bill_Jaffa
    January 17, 2013

    Naysayers, deniers, whatever–that old analog reality will sneak up and bite them in the you-know-what, there's no avoiding it for most real designs,

  13. Shafik
    January 17, 2013

    I agree 100% with Bill's article!

    Try to use your cell phone without an antenna!

    Antenna is just an LC analog filter!

    Try to use your hybrid car without the power analog filter for your electric motor,

    you will be at your garage the next day for a new electric motor.

    Try to compare the speed of an analog multiplier with a digital one.

    The first one works is on real time!

    Try to run a microprocessor without an analog filter at the input of the signal.

    Try to measure the EEG signal (10 microvolts) with a digital systems!

    Analog is alive and will stay for a very long time.

    The story of Linear device that was just bought by Texas is an eloquent description of the position of the analog in the electronic market.

  14. Normie01
    January 18, 2013

    An old EETIMES Immortal works caption for Admiral Nelson at the Battle of Trafalgar said, “Where the hell am I going to find an analog engineer that doesn't smoke everything he builds?”

    On a lighter vane (vein?), the whole world is an analog stage in which digital folks play bit parts.

    I'm proud to be one of 'them there' analog types.  All problems are analog in nature.  Sometimes, with proper conditioning, we can find digital solutions.

    Welcome aboard, Bill.

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