Page 1 of 1
4 A/D receiver for 4 antennas
Posted: Tue Sep 12, 2017 8:09 am
by s52d
Hi!
Is there a ossibility to link two (or more) RPs in a way so clocks and FPGAs are synchronized?
Main goal is 4 times RX diversity: thus, phase synchronization has to be kept
over filtering/decimation process beside common A/D clock.
Best reagrds, 73
Iztok, S52D
Re: 4 A/D receiver for 4 antennas
Posted: Tue Sep 12, 2017 8:49 am
by pavel
Hi Iztok,
In my opinion, Red Pitaya isn't the most suitable board for the 4 times RX diversity. A solution with one FPGA and four synchronized ADCs would be more suitable for this kind of project.
At the following link, you can find a solution based on the Digilent Zedboard and Analog Devices
AD9253 ADC evaluation board:
http://g4guo.blogspot.be/2016/04/back-d ... oject.html
Best regards,
Pavel
Re: 4 A/D receiver for 4 antennas
Posted: Tue Sep 12, 2017 11:10 am
by s52d
hi Paul!
Thanks a lot for the answer.
I've been looking at AFEDRI
http://www.afedri-sdr.com/.
12 bit A/D, two ch. standard, 4 ch available. Works with linrad (2ch).
It is in red pitaya price range ...
RP is 14 bit/ but lacks low pass filter and preamplifier.
Also, FPGA is more capable: your code to have 6 separate receivers is perfect.
If they can be split to two A/Ds, thus having two RX diversity on 3 separate frequency bands.
How about an idea:
Take two RP boards. use common 125 MHz clock. connect two RX antennas to each of RPs.
generate sync signal with master RP D/A and feed it into all receivers.
Would it be possible to obtain phase sync over all inputs?
BR
Iztok, s52d
Re: 4 A/D receiver for 4 antennas
Posted: Tue Sep 12, 2017 12:40 pm
by pavel
If they can be split to two A/Ds, thus having two RX diversity on 3 separate frequency bands.
Yes, they can be split. The inputs corresponding to each receiver are the command line arguments for sdr-receiver-hpsdr.
How about an idea:
Take two RP boards. use common 125 MHz clock. connect two RX antennas to each of RPs.
generate sync signal with master RP D/A and feed it into all receivers.
Would it be possible to obtain phase sync over all inputs?
You'll also need a reset signal simultaneously resetting both ADCs and FPGAs.
Re: 4 A/D receiver for 4 antennas
Posted: Tue Sep 12, 2017 12:53 pm
by pavel
BTW, the combination of ZedBoard and AD9253 evaluation board costs less than four AFEDRI boards:
Re: 4 A/D receiver for 4 antennas
Posted: Mon Oct 30, 2017 3:11 pm
by JB
Hi Iztok,
this might be a bit too late, but there is a project which synchronizes multiple RPs:
https://www.koheron.com/blog/2016/11/29 ... ya-cluster
This can be exended to the ADCs with a bit of soldering.
Greetings
Jonas