AD831 with BFO as product detector?

[ChristofferB]

Hi! I've become a massive fan of those little cheap ebay SMA boards from China, especially the AD831 and LNA ones. I try to use these boards as blocks for building RF gear as much as possible, and i've wondered if one of these would do as product detector for an SSB receiver? the output would be AF, of course, so i'd have to short the RF decoupling cap on the IF side, but would it function as such?

I've always had a hard time understanding if a product detector really just is a mixer or what.

[danadak]

Looks like the 2'ond mixer in this design is used as a product
detector.


http://lea.hamradio.si/~s57nan/ham_radio/ssb_80m/ssb_80m.html



Regards, Dana.

[cncjerry]

Did you find the AD831 to be low noise?  Decent performance vs a passive like TUF-3 etc?  I've had one sitting around since inception, never built out the circuit.

Thanks.

Jerry

[ChristofferB]

true, that's looks as if it's been done before! i'm gonna try it!

-I've had great experiences with the AD831 in previous projects! I can't really compare it to a passive mixer, but considering the convenience in that it also has some gain, it's given me the greatest sensitivity of any SSB RX i've built. Note that this could be the result of more factors than just the mixer, though.