Re: [Discuss-gnuradio] Re: Low cost hardware option

[Moeller]

On 15.01.2011 13:45, Patrick Strasser wrote:
> For flexibility, being able to bypass stages or feed signals e.g. at the
> ADC would be cheap. Preparing for different transport systems would make

I wonder how much noise will be introduced with a switch at the ADC.
At least I would use 2 different input connectors, because switching
in front of the LNA would surely introduce too much noise (except
some special shielded RF relays).

> it more future proof. If USB3.0 hardware support is not satisfying now,
> maybe it is in two years. For the data bus part this would require a
> prepared interface for data and control lines.

At least the USB3.0 solution would be backwards compatible to USB2.
So it does not harm for older machines.

> I see the target for such at above all the soundcard solutions and below
> the USRP1. USRP1 can do 8MHz Bandwidth complex at 14bit/sample RX, which
> is more than enough for hobbyists. What would be interesting for

Is this the limit? I was reading that the usable bandwidth (below line speed)
is about 40 MB/s, so about 10 MS/s complex or 10 MHz baseband.
It's not more than enough, but I could live with that restriction
(if it's for a good low-cost compromise).

> university teaching and research? What would be interesting for other
> potential users, like hams? Did I miss some?

Yes, children and adult who like to play with electronics at home.
It could be an oscilloscope, spectrum analyzer, signal analyzer,
logic analyzer (ok, only 1 channel), signal recorder ...
People who don't make profit with it, have no university or tax-paxer
to finance the box ... all those who can't pay the price of $1000
for USRP (incl. tax, shipping, RF boards etc.)

> For a start, a not too expensive, but still capable system with options
> for extension seems most doable for me. If the transport systems is to
> be fully integrated in the first shot, at least the data should be
> accessible via some interface.

I agree to start not too expensive. The advantage of open-source community
projects is, that it will be easy to modify the design later,
replace controllers, upgrade RF mixers or replace ADC by faster ones.