I successfully built a project where an arduino communicates with another through a RTF-SAW Aurel 433 MHz transceiver.
But I can't understand WHY it works, as I examined received signal, and it's full of noise! Dozens of spurious high bits mixed with actual signal sent by the transmitter!
Maybe it depends on how I wired the transceiver?
Can anybody provide a link to a working project using arduino and this transceiver, to see how they're connected? I followed instructions on datasheet, so all should be fine (and it is, apparently, as two units communicate), but something is wrong somewhere.
It is not clear how "something is wrong" if the project is successful and the Arduinos communicate?
It's not clear to me, too... 
WHERE did you look at the received signal?
At the RX pin.
Noise appears as strong as signal!
I sampled signal using audio card of my PC, which works fine in sampling signals by connecting to the RF module of the base of my weather station.
This is an example:
In first line you see a signal burst on the right; all the remaining should be silence! :-?
And it IS silence, if I connect to a 433 MHz receiver on the weather station, hence there is no 433 MHz noise here around. Or maybe there's a very good filter on that module? But I can't identify any other chips on it than an OpAmp, so can't say how it works.
I think this "noise" is way to high to be actually called "noise", there's someting wrong here around.
You probably have one in your computer right now.
Intel inside? 
Lefty
You are looking at DIGITAL noise. It will ALWAYS be 5V by definition.
Good point.
Actually the receiver in the weather station looks like an analog circuit , so probably that's why it has no noise... :-?
My transceiver has also analog output, Il'' take a look at it.
Anyway, I have another problem: I wired also two separated modules, a TX433SAW and an AC-RX2 (both Aurel).
I took this picture:
First line: signal I read in the receiver when I press a key on a radio remote control.
Second line: signal I read as output from arduino and input to TX module
Third line: signal I read as output of the same RX of first line, but when receiving the signal sent from the Aurel TX connected to Arduino.
???
What's going on?
Datasheets:
TX: http://www.futuraelettronica.net/pdf_ita/8110-TX433SAW.pdf
RX: http://www.futuraelettronica.net/pdf_ita/8110-AC-RX2.pdf
We have been using similar SAW units for Dirt Cheap Dumb Wireless, see http://www.dcdwireless.com/index.htm the bottom third of page.
These SAW transmitters and receivers are simple beasts with no squelch, and OOK (On-Off Keyed) modulation, therefore in the absence of a valid input they chase themselves into the thermal noise floor. The noise looks like Boltzman thermal noise kTB filtered by the receiver bandwidth. The threshold adapts to slightly less than the average of this noise, and gives a decent dynamic range for either strong or weak signals. It will chase a weak signal down to the noise floor, if no RF it will threeshold on the noise.
Prashanth Holenarsipur of Maxim has article in December issue of DigiKey Tech Zone Magazine called "I'm OOK - You're OOK ?" you can go here http://www.digikey.com/us/en/mkt/techzone-magazine.html, click on the Dec 22 issue and turn to page 8.
This is normal. We at Dirt Cheep Dumb Wireless wrote our software to ignore this.
I'm discussing about noise in these receives in another thread first part of the thread; here Now I'm discussing about not being able to properly receive signal in a receiver which successfully receives same signal if produced by a different source.