Any low power low frequency quadrature receivers?

Paltry? I think it's a 20-bit ADC.

ming

won't

ore in

d? Or

d...

:-)

ll

xers

ps,

you can get a dual dpdt switch in 3x3mm qfn maybe one of those as mixer ?

-Lasse

Yes, but AFAIR if you need any reasonable speed like tens of KSPS it'll drop to much less.

True. 20 bits at up to 187 SPS, 16 bits at up to 48k SPS, 12 bits at up to 192k SPS.

I know that's not the best, but for an on-board I thought it pretty good.

If it was 16bits up to 192kbps I'd be really happy :-)

Ok, so now I know your definition of paltry ADCs.

Sounds like a nice idea. IIRC the ADC on NXP ARM devices can be triggered by a pin as well.

That and a megabuck or two.

I've done that using CMOS switches as well, about 19 or 20 years ago.

Regards, Allan

Yes, you can use a PWM output routed back to a pin to trigger the ADC

It's 12bit, 2MSa, with a couple of LSB max error

/klaus

With a direct conversion receiver that won't work too well. One issue is that in many applications there is a substantial DC bias on the signal which is essentially useless and must be stripped. Done with a capacitor in analog but when using the ADC as the downconverter the DC part eats up a lot of its dynamic range.

The other challenge is in-band noise from other signals that can be much stronger than the one you want to listen to. The pre-filter can only do so much. 16 bits would be nice. The more the better, of course :-)

Depends on how compelling your evidence is. I've so far never had to go to the mat on any legal stuff. The (very) few times it came to a head there the guys looked at the evidence and decided to bury the hatchets.

CMOS switches make pretty good mixers. Good MOSFET mixers have a higher IP3 than just about anything--I still miss the late lamented Si8602.

Cheers

Phil Hobbs

If you ever come across the absolute cat's meouw for any sort of analog chip get a tube of them. That's what I did with the mother of all mixers, the Plessey SL6440. Just in time before it all went under. Same with the LH0063 and LH0033, because they never made anything even remotely comparable and I kind of knew they wouldn't.

Well, there was the LH4008/4009, but they went away first.

I have a reel of BF862s, and will probably get one of NE38143s. I also have several hundred BFG25A/W's and a bunch of MC1496s in various packages.

(I also just got another SD-24 for $100 even.)

Cheers

Phil Hobbs

Cheers

Phil Hobbs

Simple analog bandpass filter of the incoming signal, syncronize a ADC from a PWM Local Osc generated by the micro, use a low frequency FIR filter to regenerate the shifted down signal from the undersampled output of the ADC.