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Design >> RF Design >> What happens after the ADC in a wireless receiver...?
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Message started by solanojedi on Jun 10^th, 2014, 1:04am

Title: What happens after the ADC in a wireless receiver...?
Post by solanojedi on Jun 10^th, 2014, 1:04am

Hi everyone,
this question is probably off topic but I'll try.
I'm an analog RF designer, mostly involved in analog blocks design for wireless communications (LNA, mixers, op amp etc...). I was just curious (and ignorant...) about what happens to the digitized received signal in a receiver, after the ADC. For me, the digital baseband is still a mistery.

Could you suggest me some books or papers that describe what happens and could be useful and understandable for an analog designer?
Thanks a lot in any case!

Title: Re: What happens after the ADC in a wireless receiver...?
Post by aaron_do on Jun 11^th, 2014, 10:32pm

Hi,

I don't know very much about it, but I recommend you read about communications networks and the OSI model layers. I guess you're most interested in the PHY layer which directly follows the ADC.

regards,
Aaron

Title: Re: What happens after the ADC in a wireless receiver...?
Post by solanojedi on Jun 12^th, 2014, 3:50am

Hi aaron_do,
thank you for your reply. Yes, I'm actually interested in the (even conceptual) operations that follows the digital conversion of the signal (like the role of the matched filter: it is always present? Nowadays is implemented in the digital domain?).
Actually I found this book that seems to cover these topics, but probably from a 'system' or 'high-level' point of view: http://books.google.it/books?id=Icq1bNpr3xUC&printsec=frontcover&hl=it#v=onepage&q&f=false

Title: Re: What happens after the ADC in a wireless receiver...?
Post by aaron_do on Jun 12^th, 2014, 5:50pm

Hi solanojedi,

as far as I know, matched filtering is always done in the digital domain as its not really possible to design matched-filter shapes in the analog domain. As for whether its always included, I think it entirely depends on the application. Check out this webpage:

http://www.seasolve.com/802-11b-phy-ip-core.html

this company is advertising their PHY core (navigate to the block diagram), and you can see the huge difference between the 802.11b and g (uses OFDM).

regards,
Aaron

Title: Re: What happens after the ADC in a wireless receiver...?
Post by loose-electron on Jun 13^th, 2014, 12:56pm

This is a mix of communication channel signal processing (think things like DSP filtering followed by OFDM or n-Mary demodulation systems) and items associated with protocols and higher levels of digital processing associated with routing, ECC, etc, etc.

And it varies from standard to standard.

Suggest getting some books on the subject of phone systems end to end or reading up on the WiFi standards or something similar.

Title: Re: What happens after the ADC in a wireless receiver...?
Post by solanojedi on Jun 16^th, 2014, 5:08am

Thanks everyone!!