[USRP-users] Phase Noise for USRP N200 with LFTX/LFRX

khalid.el-darymli khalid.el-darymli at mun.ca
Tue Dec 9 07:53:15 EST 2014


Thanks very much for this information. According to the datasheet you
mentioned in the link below [1], the supported oscillating frequency by
CVHD-950 is 50 MHz to 130 MHz. The PN specs are provided for some center
frequencies in this range.

However, I am interested in the HF band for which the LFTX/LFRX support
center frequencies up to 30 MHz. For requested center frequencies in (DC,
30 MHz], do you digitally down-sample the center frequency of CVHD-950? Is
there any description on how exactly you do that? and what effect does this
may have on the phase noise of CVHD-950?

I am working on an ocean-based HF radar. Basically, the system measures the
Doppler frequency of ocean waves for different sea states. It is important
that I characterize my system to know its limits and capabilities.

Thanks for your help.

Best,
Khalid

[1] http://www.crystek.com/home/oscillator/vcxodetail.aspx?pn=CVHD-950

On Mon, Dec 8, 2014 at 7:35 PM, Matt Ettus <matt at ettus.com> wrote:

>
> With the LFRX and LFTX, there is no mixer, so all phase noise is from the
> ADC clock.  The oscillator used is a CVHD-950 from Crystek and you can find
> the phase noise spec for it on their web site.
>
> Matt
>
> On Mon, Dec 8, 2014 at 2:11 PM, khalid.el-darymli via USRP-users <
> usrp-users at lists.ettus.com> wrote:
>
>> Hi,
>>
>> According to the specs provided in [1], the RF performance of USRP
>> N200/N201 is characterized for the WBX daughter-board. Particularly, phase
>> noise measurements are given for three offsets from a center frequency of
>> 1.8 GHz.
>>
>> My question is, are there any such measurements for the LFTX/LFRX
>> daughter-board?
>>
>> If not, is there a recommended procedure for doing these measurements?
>> Among others, I am particularly concerned with the phase noise and its
>> short-term effect on my Doppler measurements.
>>
>>
>> [1]
>> https://www.ettus.com/content/files/07495_Ettus_N200-210_DS_Flyer_HR_1.pdf
>>
>> Thanks,
>> Khalid
>>
>>
>> _______________________________________________
>> USRP-users mailing list
>> USRP-users at lists.ettus.com
>> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>>
>>
>
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