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alexe100
PostPosted: Nov 11, 2009 - 11:38 AM
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Joined: Mar 12, 2008
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Hi,
Could you please explain me if there is possible to implement (by hand) the 802.11 norm in a nordic 2.4GHz transceiver (nrf2401).

Is it possible to communicate directly from a nordic 2.4 GHz and and a wifi access point?

Both use the 2.4 GHZ band right? What is the diffeences between transceivers?

Thanks a lot

Alex
 
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Guillem Planisi
PostPosted: Nov 11, 2009 - 12:47 PM
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Although I'm not an RF guy, I bet that Nordic transceiver uses a single frequency and a fixed (and narrow) bandwidth, while WiFi uses higher bandwidth and different frequencies that vary along the time in a pseudorandom order, with a much complex RF modulation (google for Direct Sequence Spread Spectrum to have a clue, although WiFi uses different schemes).

In short: RF modulation done by the transceivers differs.

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ka7ehk
PostPosted: Nov 11, 2009 - 04:47 PM
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Joined: Nov 22, 2002
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Location: Tangent, OR, USA

There are many 2.4GHz "users". 802.11 (WiFi), 802.15.5 (Zigbee, XBee, etc). They use non-compatible modulation schemes including spread spectrum just so they do not interfere with each other.

The nRF2401 does NOT appear to fit any of the "standard" protocols. Therefore, do NOT expect it to be able to connect to anything else besides other nRF2401s. The description says:
Quote:
Air compatible with Nordic nRF2401A, 02, E1 and E2
If it is compatible with WiFi, it would certainly say so because that would be very valuable.

Jim

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leon_heller
PostPosted: Nov 11, 2009 - 05:28 PM
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Those Nordic RF chips use their own low-level protocol.

BTW, the nRF2401 is obsolete. Use the nRF24L01+ instead.

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stevech
PostPosted: Nov 11, 2009 - 08:34 PM
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Nordic, cheap. Good.
Nordic, proprietary protocols. Bad.
Nordic's second source, none. Bad.
 
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leon_heller
PostPosted: Nov 11, 2009 - 08:57 PM
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There are several non-proprietary protocol stacks for the Nordic chips; I don't think that Nordic has one of their own. What wireless chips are second-sourced?

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alexe100
PostPosted: Nov 11, 2009 - 09:56 PM
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Joined: Mar 12, 2008
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Thank you very much for your explanation.

Alex
 
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stevech
PostPosted: Nov 12, 2009 - 02:53 AM
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leon_heller wrote:
What wireless chips are second-sourced?


all the 802.15.4 chips and modules are, on the air, the same, for a given band such as 2.4GHz, at the MAC and PHY. There about 6 chip vendors and about 15 or 20 module vendors using those chips. Atmel is a chip vendor.

as are 802.11 chips/modules.

as are 802.16 chips/radio end-items.
 
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leon_heller
PostPosted: Nov 12, 2009 - 06:46 AM
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That's not really second-sourcing, if the chips aren't interchangeable.

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stevech
PostPosted: Nov 13, 2009 - 03:20 AM
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leon_heller wrote:
That's not really second-sourcing, if the chips aren't interchangeable.


It is, to me, if you have a big project dependent on 802.15.4 and you must change vendors. The air interface stays the same.
 
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