On Wed, Jun 20, 2012 at 8:11 AM, Alexander Chemeris
<alexander.chemeris(a)gmail.com> wrote:
On Wed, Jun 20, 2012 at 5:33 AM, Thomas Tsou
<thomastsou(a)gmail.com> wrote:
On Mon, Jun 18, 2012 at 1:31 AM, Alexander
Chemeris
<alexander.chemeris(a)gmail.com> wrote:
Nothing really tested yet. At least you should do
this steps:
./umtrx_lms.py --lms 1 --lms-rx-enable 1
./umtrx_lms.py --lms 1 --lms-rx-pll-tune 925e6
./umtrx_lms.py --lms 1 --pll-ref-clock 26e6 --lpf-bandwidth-code 0x0f
--lms-auto-calibration
Then you need to select Rx input with register 0x75. Should be
something like this:
./umtrx_lms.py --lms 1 --reg 0x75 --data 0xF0
There are a lot of other settings for Rx fontend in LMS which I don't
understand, but I guess defaults should be fine for the start. Then we
could tune them with Andrey's help.
If signal is too low you may need to tune Rx VGA2 gain with the
register 0x65 (refer to the programming guide for the register values
encoding).
Connected a call - all seven actually. It's quite stable once setup.
Good job!
How did you setup Rx on LMS?
And anything else to know before testing?
'fairwaves/umtrx' branch with
u2plus_umtrx-20120424.bit and following
patch.
Now it's time to make this a configure option. :)
I and Q were swapped.
So I/Q order is different at Rx and Tx?We could fix this in FPGA.
With the multi-ARFCN support, do you think it will be hard to add
support for the second channel in UmTRX to OpenBTS to get 15 calls?
Second channel is not fully supported by UmTRX FPGA firmware yet, but
we should do this soon.
Actually interesting would be to test UmTRX with your multi-ARFCN code
to see how many channels we could fit into.
I wonder how do you select/measure rx_smpl_offset. My guess is that
you write both Tx and Rx I/Q streams to files, plot them and try to
align frame starts. Is that how do you do this?
PS Could you record a short video of making 7 calls through UmTRX? We
should make some noise or people forget what we're doing.
--
Regards,
Alexander Chemeris.
CEO, Fairwaves LLC / ООО УмРадио