LMS TxLO noise

Alexander Chemeris alexander.chemeris at gmail.com
Mon Jul 30 13:54:48 UTC 2012


Hi all,

Schematics are updated:
https://github.com/chemeris/umtrx-schematics/commit/e4f71edbe96d4673ce87e6db982c0346a9b6e412

Huge thanks to everyone for digging into the issue!

On Mon, Jul 30, 2012 at 12:07 PM, Andrey Sviyazov
<andrey.sviyazov at fairwaves.ru> wrote:
> Hi Thomas.
>
> Thank you very much for good news.
> Sylvain and everybody who discussed, thanks a lot.
> Seems, now I could finalize new revison of the BOM.
>
> Best regards,
> Andrey Sviyazov.
>
>
>
> 2012/7/30 Thomas Tsou <ttsou at vt.edu>
>>
>> Hi Andrey,
>>
>> Parts arrived yesterday and I made modifications for the 100 kHz loop
>> filter and tested today. The entire 900 band is below 1.5 / 5 with a
>> good margin.
>>
>> http://filebox.vt.edu/users/ttsou/http/umtrx_945mhz_4.bmp
>>
>> The lower part of the 1800 is also below the target value. I was not
>> successful at 1885 MHz, though further calibration is possible (manual
>> calibration at each frequency takes a very long time). I will perform
>> additional tests tomorrow.
>>
>> http://filebox.vt.edu/users/ttsou/http/umtrx_1825mhz_4.bmp
>> http://filebox.vt.edu/users/ttsou/http/umtrx_1825mhz_noise.PNG
>>
>>   Thomas
>>
>> On Wed, Jul 25, 2012 at 9:52 PM, Thomas Tsou <ttsou at vt.edu> wrote:
>> > On Wed, Jul 25, 2012 at 1:41 PM, Andrey Sviyazov
>> > <andrey.sviyazov at fairwaves.ru> wrote:
>> >> Hi Thomas.
>> >>
>> >> Digikey part numbers links:
>> >> C82 = 100pF, C83=1500pF, C84=33pF, R106=2.2k, R109=3.3k, L6=0.022uF.
>> >>
>> >> But you'll remove 100pF capasitor from position C45, so you could use
>> >> it for
>> >> C82.
>> >> BTW, how long time required to delivering from the DigiKey?
>> >
>> > Thank you for the links. Parts are ordered. Digikey orders usually
>> > arrives in 2 days.
>> >
>> >   Thomas
>
>



-- 
Regards,
Alexander Chemeris.
CEO, Fairwaves LLC / ООО УмРадио
http://fairwaves.ru




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