LMS TxLO noise

Alexander Chemeris alexander.chemeris at gmail.com
Wed Jul 25 04:46:49 UTC 2012

Hi Andrey,

Could you also describe to Thomas and Sylvain what to do with C45 and
L6? I guess that's a required step before they do any other

And please, add this issue to the issue tracker.

On Wed, Jul 25, 2012 at 1:56 AM, Andrey Sviyazov
<andrey.sviyazov at fairwaves.ru> wrote:
> Hi Thomas.
> Could you please make test again for LO integral phase noise and modulation
> accuracy with PLL loop filter 100kHz and ICP=0.4mA (or above), as Srdjan
> suggested us.
> I've assembled 100kHz loop filter with the next components:
> C82 = 100pF, C83=1500pF, C84=33pF, R106=2.2k, R109=3.3k.
> To get good noises replace choke L6 by capacitor 10nF..22nF and remove C45.
> I ask you because I have to send final BOM as soon as possible to avoid
> delay of UmTRXv2 production due to changes for improvements.
> Best regards,
> Andrey Sviyazov.
> P.S. Pictures attached just to be sure.
> 2012/7/23 Andrey Sviyazov <andrey.sviyazov at fairwaves.ru>
>> > > Perhaps this is a silly question, but how do I calibrate the clock? or
>> > > use an external reference signal?
>> >
>> > Andrey Sviyazov - does ClockIn works as external input in UmTRXv1?
>> Yes, 5V cmos level required or smaller with DC offset to get 2.5V
>> symmetry.
>> Turn switches to MHz and slave positions.
>> Best regards,
>> Andrey Sviyazov.
>> (Sent from my mobile client)

Alexander Chemeris.
CEO, Fairwaves LLC / ООО УмРадио

More information about the UmTRX mailing list