OLPC hardware: what if there was an SDR modem / chipset?

John Watlington wad at laptop.org
Mon Jan 25 22:22:09 EST 2010

On Jan 26, 2010, at 2:07 AM, Luke Kenneth Casson Leighton wrote:

> On Mon, Jan 25, 2010 at 6:05 PM, Luke Kenneth Casson Leighton
> <lkcl at lkcl.net> wrote:
>>  the key questions to be asking are: in light of the massive volumes
>> involved with OLPC XOs, is SDR worth pursuing, given all the
>> development costs, but given all the benefits especially where SDR  
>> can
>> be re-programmed to do "whatever" in bands where licensing and
>> regulatory approval is _not_ required, on a per-country basis?
>  bearing in mind that the particular R.F. front-end transceiver chips
> i'm looking at, one can do 600mhz to 6ghz and the other can do 100mhz
> to 6ghz.  there's another one which can do 80mhz to around 5ghz or so
> i believe, but it's "receive only" but has far superior
> signal-to-noise ratio and is accompanied by a far superior A2D-USB2
> converter.

A USB2 interface is used to talk to the A/D ?
I just eliminated all the internal USB buses in the XO...
I'm not against SDR, but this chip doesn't sound
compatible with our power/cost budget.

More importantly, this sounds like it is years
of software development and testing from being
a real product.   OLPC doesn't have the resources
to fund this development.

Re certifications, on both XO-1 and XO-1.5 we
use slightly non-standard modules (on XO-1 to
support 802.11s, on XO-1.5 to reduce power
consumption by 50%) and have payed the full
certification costs.   They run about 100K$ for
starters, with each additional country adding
around 5K$.


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