25 Nov
2015
25 Nov
'15
6:33 a.m.
Hi Sylvain.
Sorry for so delayed reply, I've found that I've lost subscription for this
mailing list.
Well, actually DC/DC were synchronized (between each other) even in the
very first UmTRX version.
On the first versions I saw spurs from DC/DC ~500 kHz at the TxPLL noise
plot (few in case of non-sync) and some other surprises.
You can see issue #42 here:
https://code.google.com/p/umtrx/issues/detail?id=42&can=1&colspec=I…
Nowadays, we use DC/DC chip TPS54560, synchronized to 541 kHz signal
(26/48) from FPGA.
No surprises noticed anymore, but actually, we chose TPS54560 because of
better efficiency and higher input voltage.
Best regards,
Andrey Sviyazov
---------- Forwarded message ----------
From: Sylvain Munaut <246tnt(a)gmail.com>
Date: Sun, Nov 8, 2015 at 11:12 PM
Subject: Regulator Synchronization
To: umtrx <umtrx(a)lists.osmocom.org>
Hi,
I know that on the UmTRX the switching controllers ( ST L5973 ) are
all synchronized together.
IIRC the earlier versions of the UmTRX didn't have this and I'm
wondering if you really noticed a difference due to this change ?
Cheers,
Sylvain