The art of electronics

Your really asking that when we have Obama, Pelosi, and Reed?

The electronics is, but who writes 68k's in assembly anymore? (Highland doesn't count. ;-) Some ARM code would be more appropriate, but it's not so much the architecture anymore because everyone uses C anyway.

Or Li ion. NiMH isn't that new, is it? NiCds have been around for ages anyway, and work about the same.

I would definitely like to see more on switching supplies: it's not like they didn't exist until the WWW was invented. Switching supplies have been around for centuries*, and they're more important than ever. And I find them quite fascinating.

That, and power systems in general (which are usually switching systems). I suppose that's getting closer to its own subject, with its own textbooks, but still.

Some actual RF design wouldn't hurt. It's just skimmed over. The process of designing some sort of radio system, it could be VHF or UHF range, manually or electronically tuned, maybe not PLL'd, with whatever detection scheme, would be neat. A radio wouldn't run into the potential problems that designing a radiotransmitter could have (i.e. FCC licensed output). VHF-UHF is an interesting band, two sided PCB handles it just fine but it still requires careful layout and better-than-2N3904 transistors to amplify.

*A Whimhurt generator is just a flying-capacitor charge pump, so there. :-p

Tim

--
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms

It's only a transmitter if you stick an antenna on it; otherwise it's just lab equipment -- a signal generator. :-)

Propagation in VHF/low UHF is also a lot more favorable than the "microwave" bands, particularly for traditional analog modulation schemes. (No fancy digital rake receivers!)

---Joel

As a hobbyist that's something that I've always wanted to find - a text with some examples of the thought processes that go into various RF designs. I'd like to learn more RF design, and I have what I think are two decent references - Bowick's RF Design book and "Introduction to Radio Frequency Design" by Wes Hayward, but neither of them really have any examples of how things come together at the system level. So in studying this on my own I'm left knowing a lot about how to calculate the Q of a parallel tuned circuit and how to read a Smith chart, but not how to actually BUILD anything! D:

On a sunny day (Thu, 21 Jan 2010 16:43:51 -0500) it happened Bitrex wrote in :

Old RSGB radio handbook.

You might try looking into something like this:

There are a couple of approaches to overall radio design...

1) You design everything at a high level, starting with deciding what kind of power input you'd like to see at your antenna input to provide a given output (e.g., a 12dB SINAD for analog systems, or 1e-6 BER for digital systems, or whatever). Then you just start tossing in filters, mixers, amplifiers, etc. into whatever arrangement you feel like to achieve that goal, generally use a well-defined interconnect strategy (i.e., system impedance such as 50ohms). :-) There are plenty of very well-known architectures to choose from (e.g., super heterodyne) -- examples of receiver or transmitter architectures are generally found more in "communications" books that RF books, although there's certainly plenty of overlap. Anyway, then, once you have your block level diagram, you start purchasing or designing the individual components, hook it up, and see what happens.

Military radios are usually built this way -- very modular, easy to troubleshoot, but also big and expensive.

2) You start as above, but don't worry about the interconnects so much... you design or copy or buy some, say amplifier or whatever that you like and hook it to say, some mixer that you have, and see what happens. If it's still "good enough," you keep adding more pieces until the radio does what you'd like it to do.

This is how many of the circuits you see in amateur radio circles are designed. People use the same or slight variants of some well-known circuit they've designed or previously used again and again, and even though the overall design is unlikely to be completely optimal, it's often good enough. When suddenly you hook up another bit of circuitry and performance drops like a rock, you sit down and try to figure out why, e.g., maybe this is a big enough impedance mismatch between stages that you're now losing gain rather than adding it.

This book:

...is largely focused on this technique with the addition that (as Hayward mentions in the book you already have) there's often room for significant improvement in mixers and amps and what-not, so you'll find a chapter where someone tries to optimize some small section of a receiver, etc. If you look at one of the author's web pages: ...you'll see that he's big on, "let's try to build a single-transistor RF amplifier and see what happens," "let's try to build a mixer and see what happens," etc. -- but then he takes the results of those articles and packages them up into "let's build a simple SSB receiver using my single-transistor RF amplifier, mixer, phasing network, etc. that I designed previously..."

3) You start as in 2, but then make an effort to start combining or eliminating all the circuitry you can to effect cost reductions which retaining acceptable performance. As a result, at some point it's often no longer at all "obvious" exactly how component values were obtained or circuit topologies chosen -- they've morphed a lot from any "textbook" image you'd find.

This is what you get in, e.g., those $5 walkie-talkie toys for kids, where you see designs such as a single transistor that functions both as an (the gain component of an) RF oscillator and an audio amplifier. ...Possibly at the same time!

Historically these sorts of designs were often massively copied from one company to another -- it wasn't uncommon in the '80s to see $4 AM radios that had 100% identical schematics, despite coming from two different Taiwanese companies.

There are books just on system-level design (e.g., "Practical RF System Design" by Egan), but honestly, it's not the kind of book I'd suggest you want to start out with -- until you've seen the kind of damage intermods and compression and mixer spurs do to your radio systems first-hand, it won't be obvious just why what he talks about it as important as it is. :-)

--
At the end of the day you pretty much have to sit down and decide you want to 
build something.  E.g., decide that you'll make your own FM receiver or 
transmitter for the 2m amateur radio band.  From that, a lot will follow 
naturally... you'll figure out some block diagram, decide if you just want to 
buy mixers/amps/filters-in-a-can vs. designing your own, etc.  The first thing 
you build will probably work rather poorly, but that's OK -- you'll know where 
its shortcomings are and can move on to an improved design.

If you haven't done much electronics construction/experimenting before, you 
might get yourself something like this: 
http://www.tequipment.net/ElencoAM_FM-108TK.html ...and then proceed to try to 
replace sections of it yourself or replace components to tune it to different 
bands or something.

I would also suggest subscribing to QEX magazine.  And, if you have the money 
for it, attend Fours Days in May and Hamvention.  Probably 80+% of the 
"homebrewers" there are working in the HF bands, and while that does make some 
things easier, there's still a lot to be learned.  You also won't have any 
difficulty finding a few VHF/UHF/microwave homebrew guys, although they are 
rather less common.  (The microwave guys have their own little conferences 
called Microwave Update.)

---Joel

Lawyers. Not a big deal, really. Better that they put the disclaimer in and publish than not publish at all.

--
Paul Hovnanian     mailto:Paul@Hovnanian.com
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In the beginning, there was nothing. And God said, "Let there be Light."
And there was still nothing, but you could see it.

Thanks so much for all of your suggestions. I think what you say is true - if I really want to learn the process I have to set myself a design goal and follow through with it.