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Comment by analog31 | Hacker News Reader

I learned from the 1st edition, back in 1983, when I took the electronics course for physics majors. I think it's the best textbook I've ever used, in any subject. I fell in love with analog electronics. Note my HN user name. ;-)

What's happened with analog since then? I believe that opto-electronics is much more important today, as are switchmode circuits. Some things, like systematic noise budgeting, will never go away, even if we have to learn the behaviors of some new devices. Also, it's probably harder to get away with having just a limited understanding of high speed circuits and transmission lines today. But something I like about analog electronics is that physics will always be physics.

If you liked H&H, you might also like: Building Electro-Optical Systems: Making It all Work, by Phil Hobbs.

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What happened? Digital and moore's law took over. The microprocessor continues to absorb every function that, at one point, made economical sense to do in the analog domain. I share your lament, but reality instructs us to condition signals and supply voltage properly, and let the micro take it from there. It's only going to become more true as time moves on, so learn programming. Get very good at it.

And just how many serial busses, wireless networks, HDD heads, flash level detectors, and DRAM sense amplifiers did those words of yours have to travel across to get from you to me compared to 10 or 15 years ago?

Analog only looks like it's falling in importance if you divide by the size of the digital industry.

Don't forget traditional RF. How do you build a microwave low noise RF preamp using a microcontroller? Or a 1000 watt solid state broadcast transmitter using a microcontroller?

Upvoted. I definitely agree that many erstwhile "analog" functions have joined the dark side. ;-) And I've been programming digital / analog systems since the early 80s.

But I think that two challenges / opportunities remain for analog. The first is that advances in digital capabilities place new demands on analog. For instance, the possibility of higher sampling rates and bit depths requires us to go back and update transducer preamps.

Second, some archaic skills can still be lucrative if the number of practitioners decreases faster than the number of remaining applications. I'm still betting my career on the need for somebody to care about physics, while also knowing how to program. At my workplace, I am possibly the last remaining person who knows how to compute a noise budget that includes transducers, analog signals, and digital processing, in an instrumentation system.

Horowitz and Hill had a chapter, "Digital Meets Analog" that discuss ways that digital designers have to keep up with analog concepts. The ways that digital systems can go wrong are often analog.

Really curious what your job is?

I work for a company that makes instrumentation. It's one of those "okay, now what am I going to do with a physics degree" kinds of things, but it suits me well. And I've bounced in and out of management. Today, there are engineers who are ahead of me in electronic design, but I'm good at figuring out the grand overview of how products work, and like to solve weird problems. Much of my programming is in the service of solving problems, rather than creating products.

My understanding is the high fidelity audio equipment are predominantly analog and does attract people of said skillset.

I would still add another challenge for analogue: power harvesting. That's an environment where the amount of energy you can collect is so low that you can't simply afford to run a uC. However, you still need to manage that negligible amount of energy, because in the long run, it builds up, and then awesome stuff happens (switching a uC on, for example).

I bought the 2nd edition 15 years ago, I loved it, and I now cherish that useful book in my bookcase.

General purpose digital computation is often power limited (either from the supply energy or thermals of the device) and there is an (academic) resurgence of analog computation on data prior to digital blocks to reduce the power footprint of a part. Most applications of this are RF. Conditioning signals as you say these days and in the future isn't just bandwidth limiting and shifting the baseband.

I am too young to have been there for the digital vs analog debate, but I understand that things being digital was not always obvious. The reason digital won is because, very crudely, to double the precision of a digital circuit you just give it wider registers (scale horizontally), while to double the precision of an analog circuit you have to more than double the precision of every component of the system (scale vertically). Digital was/is cheaper. But, as my electronics professor put it, "every circuit is analog at some level".

The big problem is not precision in the abstract, the big problem is that analog is just about impossible to replicate reliably en masse. You could build 1000 digital circuits and they'd all come out and operate exactly identical or not at all. Your analog circuits are going to come out in a bell curve roughly between un-usable and perfect with component variation and parts count as ingredients. You can mitigate this to some extent by very careful design and pre-assembly component selection but not all the way.

The way to deal with that in the analog world is an expensive process called 'trimming' where you use adjustable components to get you where you want to be. But trimming makes the circuitry sensitive to being bounced around and makes it more sensitive to temperature changes if you use the cheap version and the expensive version (digital circuitry masquerading as trimmable analog components) puts the horse behind the cart if you wanted analog then you're no longer getting it (but some kind of quantized version of analog).

For some circuits this is all more important than for others.

Finally, digital reduces the component count and so increases reliability and decreases cost. Software is hard to make and expensive but once you have it the marginal cost of reproduction is next to zero.

Digital, once the bugs are worked out has none of these issues and so lends itself much more to economic mass production.

I'd go even further and say that you can increase the complexity of digital systems exponentially, and create functionality that just can't even be imagined in the analog realm.

But another feature, not inherent to all digital circuits but certainly prevalent, is the ability to reprogram them. For me to change an analog circuit might take hours with a soldering iron. You can load a whole new "circuit" into a digital system at the push of a button. This in turn changes how products are designed. Analog functionality is used sparingly where needed, and gotten working early in a project. The digital system is left with some flexibility, e.g., allowing changes to made later in the project without drastic hardware revision. The mantra of the analog team, at the 11th hour of the project, is: "Can we fix this in the firmware?"

As an electronics undergraduate most of us preferred digital electronics, analogue seemed like black magic. I'll always remember one of our analogue electronic lecturers scoffing at us when he had to cover a digital lab one day, saying digital electronics is just high gain analogue.

This is a problem. Need a solution? Slap a micro on it. It's a shortcut but not always the best solution. I've seen circuits using a cheap micro, yes, but someone had to program it and a simple analog circuit would have done nicely, cheaper and possibly better and more reliably.

This thought that every problem is solved with a microprocessor shows no thought being applied to the solution, not brilliance by some engineer.

If you liked H&H, you might also like: Building Electro-Optical Systems: Making It all Work, by Phil Hobbs.

+1, definitely an underrated book. It applies to a lot more than just EO systems.

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