Re: [Patch-gnuradio] Re: assert (dac_rate () == 128000000);

[Alexander Chemeris]

Hi Erik,

Could you give me some insight why high value is set to 44e6?
Coarse modulator can be set to 128e6/4=32e6 and docs says
that fine modulation has range of 128e6/4=32e6 too. Thus it should
be possible to get as much as 32e6+32e6=64e6 offset. Was 44e6
chosen because of interpolation filtering limits or smth like that?


On Sat, Dec 5, 2009 at 17:34, Eric Blossom <address@hidden> wrote:
> On Thu, Dec 03, 2009 at 12:09:02AM +0300, Alexander Chemeris wrote:
>> Hi all,
>>
>> Anyone to apply this one-liner?
>
> Alexander,
>
> The hard-coded magic numbers below the assert need to be corrected to
> to be a function of the clock rate.  You're not seeing the problem
> because of the daughterboard you're using, but if you're using a Basic
> Tx, they come into play.
>
> The existing magic numbers are particular percentages of 128e6.
> The replacements, f(clock_rate), should be the same percentages.
> They control when and which "coarse modulator" is used in the AD9862.
>
> Can you please submit a slightly bigger patch?
>
> I apologize for not writing earlier about what the problem was.
>
> Thanks,
> Eric
>
>
>> On Tue, Nov 3, 2009 at 01:01, Alexander Chemeris
>> <address@hidden> wrote:
>> > Hi all,
>> >
>> > This assert is not valid, because you may use re-clocked USRP.
>> > And we indeed do ;)
>> >
>> > Patch to remove it is in attachment.
>> >
>> > --
>> > Regards,
>> > Alexander Chemeris.
>



-- 
Regards,
Alexander Chemeris.