[USRP-users] Phase Noise for USRP N200 with LFTX/LFRX
Marcus D. Leech
mleech at ripnet.com
Tue Dec 9 10:29:25 EST 2014
On 12/09/2014 07:53 AM, khalid.el-darymli wrote:
> Thanks very much for this information. According to the datasheet you
> mentioned in the link below , 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?
No, that is the reference clock for the entire platform--driving all
timing in the platform, including the 100MHz sample clock for the ADCs.
> 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.
>  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
> <mailto: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
> On Mon, Dec 8, 2014 at 2:11 PM, khalid.el-darymli via USRP-users
> <usrp-users at lists.ettus.com <mailto:usrp-users at lists.ettus.com>>
> According to the specs provided in , 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
> Among others, I am particularly concerned with the phase noise
> and its short-term effect on my Doppler measurements.
> USRP-users mailing list
> USRP-users at lists.ettus.com <mailto:USRP-users at lists.ettus.com>
Shirleys Bay Radio Astronomy Consortium
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