On Wed, Jun 20, 2012 at 8:11 AM, Alexander Chemeris alexander.chemeris@gmail.com wrote:
On Wed, Jun 20, 2012 at 5:33 AM, Thomas Tsou thomastsou@gmail.com wrote:
On Mon, Jun 18, 2012 at 1:31 AM, Alexander Chemeris alexander.chemeris@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.