Delta-sigma A/D converter expert here?

[gentlevoice]

Hi DIYs,

I'm considering building a Delta-Sigma (or Sigma-Delta) A/D converter, more specifically a 3rd order continuous time modulator operating at 256fs.

However, I am looking either for:

- help/collaboration with somebody who knows about how to calculate and design the circuits (mainly the noise shaping and hints on potential pit falls), or

- example circuits so that I can see an example of what the circuit topology may look like. And I can't find any googling ....

I have some experience with electronics but am not sure how these circuits look in practice and how to make the calculations.

I have access to Orcad, matlab (although no experience), and LTspice.

Help is appreciated ....

Greetings from Denmark

Jesper

 

[gentlevoice]

Nobody ...?

Greetings,

Jesper

 

[Terry Demol]

Nobody ...?

Greetings,

Jesper

Jesper,

Do a search for AES papers by Bruno Putzeys. He is pretty much
-the- expert on this and has collaborated with others on the
Grimmaudio discrete 1 bit ADC.

http://www.grimmaudio.com/whitepapers.htm

cheers

Terry

 

[gentlevoice]

@ terry

Hi Terry,

Thanks for the tip...

I know about Bruno and also about the Grimm A/D converter. I've also read his article about his A/D converter, however, I need something probably a bit more basic to start out from.

BTW the only article I've found of Bruno's describing A/D converter design is the one on Grimm Audio's webpages.

Can I ask you if you know of other articles?

Best,

Jesper

 

[Terry Demol]

Re: @ terry

Hi Terry,

Thanks for the tip...

I know about Bruno and also about the Grimm A/D converter. I've also read his article about his A/D converter, however, I need something probably a bit more basic to start out from.

BTW the only article I've found of Bruno's describing A/D converter design is the one on Grimm Audio's webpages.

Can I ask you if you know of other articles?

Best,

Jesper

Jesper,

Malcolm Haksford also has a few good papers here:

http://www.essex.ac.uk/csee/research/audio_lab/malcolms_publications.html

Ref J18, J1, J2, however they are not basic so all I can suggest is
the obvious - google.

Any reason for considering such a challenging task when there are
many very high performance chip solutions available?

cheers

Terry

 

[gentlevoice]

@terry

Hi again, Terry

And thanks for suggesting the Malcolm Hawksford articles. I have taken a look at them, however, they are still a bit different from what I am looking for ....

Basically, what I (assume) I need is to find an article/book describing how to build such a modulator (3rd order, continuous time structure) with "simple" calculations and example circuitry and then I hope to be able to take it from there. Something like the structure in this article by Erno Borbely on noise in MC preamps:

http://www.borbelyaudio.com/pics/mcpreamp-pt1.pdf


You ask about my reasons for desiring to design such a converter? Well my reasons for hoping to design a delta-sigma modulator are e.g. that I have some ideas that I would like to try out. I realize that many chips are available, however, they are not really what I look for (would like to fully do without e.g. analog and digital filtering).

Hope there are some suggestions ... ?

Regards,

Jesper