Re: [Discuss-gnuradio] About clock rate of USRP E100

[Alexander Chemeris]

Hi,

On Mon, Jan 10, 2011 at 23:03, Philip Balister <address@hidden> wrote:
> On 01/10/2011 09:25 AM, Miok Wah wrote:
>> We are planning to do some experiments with USRP E100. One advantage of
>> E100
>> that we are excited with is that
>> "The user can choose (at run time) a convenient clock rate".
>>
>> Our question is:
>> 1) When we change the clock rate changed, is the main clock rate changed,
>> or
>> is it just change in the decimation rate?
>> We are asking this because we are interested in the energy consumption of
>> USRP E100. The energy consumption is likely to be reduced if the main
>> clock
>> rate is reduced, but unlikely to be reduced if it's just change in
>> decimation rate.
>
> There are two clock rates to consider: there is the fpga clock rate which is
> settable via uhd. I'm not good enough at fpga's to know how much power can
> be saved this way.
>
> The OMAP3 clock circuitry allows sections of the OMAP to be turned off, or
> clocked at lower rates to save power. This is how they use this chip in
> mobile devices. That said, the kernel and user space provided with the E100
> has the clock rate set to the max possible and does not take advantage of
> the OMAP power saving features. It should be possible to do work in this
> area with the E100 though. There is lots of activity on the linux-omap
> kernel mailing list in the power management area.

What about ADC/DAC clock rates?


-- 
Regards,
Alexander Chemeris.
http://www.fairwaves.ru