Any low power low frequency quadrature receivers?

Yes, specs are the other reason why I didn't pursue this further right now. Last time I looked at the opamp data I was not too thrilled. It's ok for mundane stuff such as control gear but for sensitive RF processing maybe not. The PSoC-3 has nice digital fliter blocks though, it may be much better than the old ones.

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Regards, Joerg

http://www.analogconsultants.com/
Reply to
Joerg
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Paltry? I think it's a 20-bit ADC.

Reply to
John S

ming

won't

ore in

d? Or

d...

:-)

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ps,

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

-Lasse

Reply to
langwadt

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

--
Regards, Joerg

http://www.analogconsultants.com/
Reply to
Joerg

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.

Reply to
John S

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

--
Regards, Joerg

http://www.analogconsultants.com/
Reply to
Joerg

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

Reply to
John S

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

--
Failure does not prove something is impossible, failure simply
indicates you are not using the right tools...
nico@nctdevpuntnl (punt=.)
--------------------------------------------------------------
Reply to
Nico Coesel

That and a megabuck or two.

Reply to
krw

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

455kHz with a 74HC4053 running from +/- 5V. I had a ring counter made from 74HC74 flip flops to make the quadrature switching signals for the '4053. This was the last IF in a 30GHz tracking receiver.

Regards, Allan

Reply to
Allan Herriman

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

Reply to
Klaus Kragelund

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 :-)

--
Regards, Joerg

http://www.analogconsultants.com/
Reply to
Joerg

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.

--
Regards, Joerg

http://www.analogconsultants.com/
Reply to
Joerg

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

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510
845-480-2058

hobbs at electrooptical dot net
http://electrooptical.net
Reply to
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.

--
Regards, Joerg

http://www.analogconsultants.com/
Reply to
Joerg

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

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510
845-480-2058

hobbs at electrooptical dot net
http://electrooptical.net
Reply to
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.

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Reply to
joey899244

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