AVR-Chat

> Analog devices has some very fast ADC chips for software defined radios.
> How much bandwidth do you need?
>
> --
> http://itsokjohn.com/
>

And what kind of signal (modulation)? There are very few "chips" that fit
these requirements. Most of what is available (as full receivers) is
tightly constrained to FM broadcast band or channelized TV reception.

The real challenge, as previously suggested, is not the selection of an IC
for the receiver. The biggie is the design of filters (antenna to linear
amplifier, linear amplifier to mixer, if, etc). This is for a more or less
conventional superheterodyne receiver. For a direct conversion, antenna to
amplifier to ADC, you have a really big challenge getting the signal
amplified to the level that an ADC can handle AND a challenge with an ADC
that has a high enough sample rate. And, with that sample rate comes a
very high bit-rate data stream. 'Tis not for the faint of heart nor the
"gotta have it now".

There are a number of "scanners" on the market that probably include that
range, but they are rarely characterized as "low noise" or "high
stability". They DO tend to offer a variety of demodulators (but rarely
handle single-sideband (SSB) very well). Many scanners seem to be limited
to a low-end frequency around 50MHz or so, though there ought to be
something lower.

There may be a few general coverage receivers out there. I would check the
HRO (Ham Radio Outlet) website to see what might be available. They should
also have scanners.

Jim Wagner, KA7EHK
Oregon Research Electronics
Tangent, OR, USA