[USRP-users] Ettus UBX-160 vs SBX-120

Simon Olvhammar simon.olvhammar at gmail.com
Tue Jul 4 04:26:49 EDT 2017


Thank you Keyong Su Shin,

However I suppose you mean aliasing just at the band edges?
I get around 100 MHz of good data when using 120 MS/s on the SBX-120
daughterboard.

Regards
Simon

On Mon, Jul 3, 2017 at 3:18 PM, Kyeong Su Shin <ksshin at uw.edu> wrote:

> Hello Simon Olvhammar:
>
> Just one more note:
>
> A relevant e-mail thread achieve, since you are apparently using ADC
> sampling rate of 120MS/s on SBX-120 daughterboards:
>
> http://lists.ettus.com/pipermail/usrp-users_lists.ettus.com/2016-February/
> 018075.html
>
> To get better data quality, you may want to sample faster and then do
> digital filtering -> decimation (USRP will do that for you, if you are fine
> with integer decimators). This may prevent you from using the 120MHz
> bandwidth, but improve the overall data quality.
>
> Regards,
> Kyeong Su Shin
>
> On Mon, Jul 3, 2017 at 1:35 AM, Simon Olvhammar via USRP-users <
> usrp-users at lists.ettus.com> wrote:
>
>> Hi,
>>
>> I am not sure if I understand correctly.
>> How are the ADC to slow if I use a master clock rate of 120 MHz and
>> sampling rate of 120 MHz on a UBX-160? I don't need 160 MHz bandwidth only
>> 120 MHz.
>>
>> Regards
>> Simon
>>
>> On 06/28/2017 04:12 PM, Sylvain Munaut wrote:
>>
>>> Hi,
>>>
>>>
>>> We currently running a system with a Ettus x310 and a SBX-120.
>>>> We also a have UBX-160 daughter board.
>>>>
>>>> For several reasons, mainly due to computer performance limitations, we
>>>> can
>>>> only run with a complex sampling rate of 120 MHz.
>>>> My question is if I will see any improvement in performance, e.g. filter
>>>> characteristics, if I instead use the UBX-160 and run it at 120 MHz
>>>> compared
>>>> to SBX-120 at 120 MHz or are they similar?
>>>>
>>> You can't do that.
>>>
>>> If you have the master clock-rate at 120 MHz and use a 160 MHz wide
>>> daugtherboard, you will get aliasing because the ADC are too slow.
>>> You'd have to go to a 100 MHz samplerate for it to work. (200 MHz
>>> sampled by the ADC then HW decimated by 2 to 100 Msps).
>>>
>>> Cheers,
>>>
>>>     Sylvain
>>>
>>
>>
>> _______________________________________________
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>> USRP-users at lists.ettus.com
>> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>>
>
>
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