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Don’t Bet Against Analog

These days we think of ourselves as living in the Information Age, an era of unprecedented connectivity and access to information that has been enabled by the Digital Revolution.

The Digital Revolution has relied on a consistent, exponential rise in the density of digital logic gates on silicon (famously doubling every two years, according to Moore’s Law). Most of the media that we use daily have converted from analog to digital formats. Think: phonograph records, analog audio tape, VHS tape, TV signals, still photography, and home movies. Clearly, the world has gone digital, and analog electronics has been left in the dust. Or has it?

Contrary to what you may have heard, all five of the human senses remain analog in nature. For information to be useful it has to be consumed by humans, who tend to have a limited appreciation for raw binary information. Likewise, most of the original sources of information are analog, at least at the level at which we experience them. So, it makes sense that analog electronics is very much needed at the human interface level and always will be.

Moreover, as consumer digital devices proliferate, the need for analog electronics to mediate to the human world guarantees that sensors and amplifiers, displays, and power management electronics will be hitching rides on the rapid growth curve fueled by Moore’s Law.

But it is not just at the human interface that this occurs. It is also at the interface between digital electronics and commonly used electromagnetic storage and transmission media. This is always likely to be true when pushing media to the limits, such as maximizing the density of information on hard drives, or picking up weak signals at the end of a long-distance radio link. Whenever signals need to be conditioned before digitization, analog electronics will be there — at the very least for anti-aliasing purposes — but usually doing considerably more than that.

As one example, consider that today’s multi-gigabit digital SerDes links usually employ continuous time linear equalizers (CTLEs) in the analog domain before they apply digital equalizers. Here is one example (among many) where the fastest digital bits need analog techniques to get along.

So, is analog electronics destined to scrape out a meager existence at the fringes of an increasingly digital world? Not unless we humans are going to allow ourselves to be digitized! Indeed, the trend is rather in the opposite direction, with pervasive computing and ambient intelligence requiring more and better analog sensors to allow smooth and natural interaction with humans and our living environment.

It’s an analog world, after all — don’t bet against it!

7 comments on “Don’t Bet Against Analog

  1. amrutah
    February 18, 2013

    Charles, Thanks for the post and I agree that analog is here to live long…

      Though the communications world is getting digitized and churning much out of silicon to achieve higher speeds, but the audio, biomedical applications,automotive applications are low power and involves a lot of analog sensors and interface…

      With the smartphone market saturating I hope other consumer products will hit the market and bet that Analog has a long life!

  2. Charles Razzell
    February 18, 2013

    @amrutah,

    Thanks for your thoughtful post, which I agree with.

    (Just an FYI: If you count tablets in with smartphones and look at world-wide sales, it seems we still have a few years of double-digit anual compound growth left, at least according to the market reports I have seen. )

  3. eafpres
    February 18, 2013

    It is interesting to see how many A/D interfaces are popping up for these tablets, smartphones, etc.  There was a big show on medical diagnostics on smartphones on TV the other week.  There are a whole range of sensors becoming available.  And even more (like thermostats) will be connected to these digital wonders by wireless technologies.  I wonder if over the long term there is more analog than digital to be dealt with out there?  If we could agree on the classification of discrete analog we could count up component sales…(see Martin Rowe's note elsewhere).

  4. TheMeasurementBlues
    February 18, 2013

    A samesman for windows shades came to my house the other day. He made the transaction with an iPad by attaching a credit card reader to the headphone jack.

    Headphone jack? I though that was output only, and just for audio. I would ahve expected the card reader to plug into the 30-pin connectors at the bottom, but no. Who knew?

  5. eafpres
    February 18, 2013

    On iPhones & iPads the jack is bi-directional becuase it also supports the microphone in little rectangular thing on the earbud wires.  It also supports control lines (volume up/down, answer, hang up, mute).  The card reader has an IC that converts the information on the card into audio tones, sends it to the app on the pad/phone, and off it goes.  Validation is done via the celluar connection on the device.

    Now–imagine how hard it would be for a decent analog guy to look at those tones on a scope, and build a card writer…or, how about malware on the device snagging the info without distrubing the app?  

  6. amrutah
    February 20, 2013

    @eafpres: This is really interesting…. I have worked on the jack part and understand the complexity involved considering it as bidirectional. I think most of the phones and tablets support bidirectional Jack (to support a hands-free device with other control signals as you mentioned)…

      Converting the digital data present on the card and transmitting a audio tone is a humongous task… this would involve some kind of digital modulation with encryption in the card reader section, a decryption and demodulation inside the iPad/iPhone and then sent over the carrier for transaction… All this looks interesting and a complex system.

  7. eafpres
    February 20, 2013

    @amrutah–some of the details can be found in the Patent which Square has for their device.

    Square Patent

    I read somewhere on the internet they are now encrypting the information so that might defuse my security comments earlier.

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