Hmmm, not a big deal I suspect.
Build a general purpose RF block for, say, 2.45GHz BT or 802.11(etc), or
whatever. Give it handles to talk with anything (modulations, bit
streams, etc.), design and build it on a particular fab process, and like
magic, anything incorporating that block will also work. Monolithic
inductors can be fabricated with not very good Q at 2.45GHz (I think they
usually peak around Q = 10 or 20 around 5GHz), but enough to do "silicon
oscillators" and stuff. Voltage regulation (bandgap, or old school buried
zener) and temperature compensation are no-brainers, as ICs go. Want a
DDS? Just chuck some more IP at it! Then whatever ancillary function
(moisture, temperature sensor, etc.) simply plugs into this mess of
transistors and functions.
Quite crazy, as all that circuitry is squeezing into a few milimeters of
silicon, when a few decades ago it was, well of course it was migrating to
thick film before monolithic, but before that, it was all machined
cavities, hand-soldered RF transistors, and microstrip everywhere. I
suppose Bluetooth would've taken up a whole rack, back in the 70s, and
that's assuming the computing power to provide whatever spread spectrum,
encoding, error detection, etc. functionality is required.
Tim
--
Deep Friar: a very philosophical monk.
Website:
http://seventransistorlabs.com
"RichD" wrote in message
...
Wireless is everywhere now, miniaturized to an astounding degree.
Recently, I saw a report on a button size gardening
gadget - stick it in the soil, it reports on moisture.
Bluetooth earphones, etc.
Who's designing these things? In my experience, RF
designers are a rare breed, and with the digital market
vastly larger, they're even rarer.
I'll guess, the IC have been perfected to the no-brainer
level. But still, you need need amps, filters, antenna, plus
issues of noise and layout, yes/no? That stuff isn't obsoleted.
I don't work in this area, but I'm curious, so can anyone
elaborate on what's going on, from a system viewpoint?
What are the chip functions, options, price, trade-offs?
In which situations would you reject them, to roll your own?
Is it simple on/off keying, or more sophisticated? Currently,
in communications theory, sensor networks are a hot topic,
where thousands of sensors are competing for bandwidth,
but for mundane consumer apps, I doubt those issues arise.
I'm looking to pick the brains of any gurus here -
--
Rich