how to enable both tx and both rx in diversity mode in ad9361 ?

nitin.vnit said:

I have modified the devicetree file to enable 2tx,2rx mode

If the 2rx2Tx mode is enabled, then by default both the TX1 TX2 and the RX1RX2 channels will be enabled.

If you want to enable and disable the channels in real time, then you can put the chip in FDD independent mode, and then use the TXNRX and enable pins to selectively disable/enable 1 or 2 channels as required. Refer to UG for more details.

Thanks for your response srimoyi . Can you please describe how to do

srimoyi said:

you can put the chip in FDD independent mode, and then use the TXNRX and enable pins to selectively disable/enable 1 or 2 channels as required

I am new to ad9361 and still exploring how to use it effectively, it would be a great help if you can guide the section in UG where this is mentioned or provide the commands for doing this.

Apart from this i am facing another issue, I am using AD5606 (CN0417) PA with AntSDR to increase the output power, The combination of AntSDR and PA is used in an adhoc network at 2.4GHz, there are two devices in this adhoc network with same hardware and software configuration. The devices can communicate with each other (ping and data sharing as well), but the distance between these two devices can not be increased beyond 200m. With Tx power of ~30dBm and antenna with 3dB gain this is not the expected distance/separation. This is why i am trying to enable diversity hoping that it will help me in getting better signal strength.

In a similar experiment with wi-fi extension boards i can get the separation to be more than 1000m, with output power of 30dBm. Can you please suggest what i am missing in configuring the ad9361 so that i am not getting more distance.

Thanks

nitin.vnit said:

am new to ad9361 and still exploring how to use it effectively, it would be a great help if you can guide the section in UG where this is mentioned or provide the commands for doing this.

Refer to the "FDD Independent Control" section in UG.

nitin.vnit said:

Can you please suggest what i am missing in configuring the ad9361 so that i am not getting more distance.

With CW tone, at 0dB TX attenuation and full scale input of  0dBFs, you should see +7dBm at the AD9361 TX output.

thanks for your response srimoyi , this does not say anything about enabling both tx channels, or both rx channels. It describes how to get Tx and Rx, Tx or Rx alone enabled. I got your point of enabling channels in real time, but i also wish to enable both Tx channels and both Rx channels. Can you share something on that please?

On second part what do you mean by full scale input of 0dBFs, also i cant see +7dBm on my spectrum analyzer, its more like 0dBm when i use antsdr at 2.4GHz.

Regards

Nitin

nitin.vnit said:

but i also wish to enable both Tx channels and both Rx channels. Can you share something on that please?

If you are enabling enable 2tx,2rx mode to 1, in your device tree, and initialize the chip, then by default both the TX and RX channels will be enabled, and nothing needs to be done apart from that for enabling both the channels in FDD mode.. Are you facing any issues while testing? Are you operating in FDD mode?

nitin.vnit said:

On second part what do you mean by full scale input of 0dBFs, also i cant see +7dBm on my spectrum analyzer, its more like 0dBm when i use antsdr at 2.4GHz.

Try increasing the input scaling of your CW tone to 2^11 and keep 0db of TX attenuation, you will be able to see maximum power at the TX output. If still, you are not seeing, then check the matching in your custom board and the cable losses.

AD-FMCOMMS2/3/4/5 Basic IQ Datafiles [Analog Devices Wiki] 

hello srimoyi 

srimoyi said:

Are you facing any issues while testing? Are you operating in FDD mode?

yes i am working in FDD mode but i am not able to get output at both Tx terminals. similarly not receiving at both rx terminals. I can check rssi at both rx channels using cat in_voltage0/1 command but both gives different output almost 25dB apart.

srimoyi said:

Try increasing the input scaling of your CW tone to 2^11

i am still not able to understand, i have a custom IP in PL sending data to AD9361 using its interface IP, how do i scale the input

Please don't mind if my question is too basic or naive.

Regards

Nitin

Are you using Linux for configuring your chip? Which FPGA do you use?

Can you check the gain readback for both the RX channels? If you are getting RSSI values for both RX1 and RX2 channels, then that means, both the channels are enabled.

Can you try testing using internal BIST tone and then check if you are able to get the output. Hope you are able to initialize the chip successfully.

AD936x Built in Self Test (BIST) - Documents - Design Support AD9361/AD9363/AD9364 - EngineerZone (analog.com) 

srimoyi said:

Are you using Linux for configuring your chip? Which FPGA do you use?

yes i am using Debian bullseye, the hardware is antsdr which is based on zynq 7z020. Yes both RX1 and RX2 antenna terminals shows RSSI but the values are drastically different. Let me try the BIST method.

Thanks for sharing

regards

Nitin

hi srimoyi , i looked into BIST, but frankly speaking i could not understand how to execute that. Hence I tried another method, i took two AntSDRs, created an ad-hoc network with these two devices. Then I tried to ping one device from the other, by plugging antennas in different combinations to check with which combinations i get the pings working. By default Tx1 and Rx1 works whereas Tx2 and Rx2 does not get me any output. Then i enabled both Tx and i was able to ping the other device with either of the two antennas, but with Rx only one chain is working at a time, i am not able to get the two Rx working together.

To enable the two Tx or Rx i am using commands available at "github.com/open-sdr/openwifi/blob/master/doc/README.md#let-openwifi-work-at-arbitrary-frequency," as the software i m trying to use is Openwifi.

Also if i enable 2Rx first and then enable 2Tx it gives command failed: Input/Output error (-5). Only with 1Rx enabled at a time I can change Tx configurations to enable either one of the two or both Tx enabled.

Can you help with this?

Regards

Nitin

hello srimoyi I tried BIST test, with AntSDR and PlutoSDR. I used AntSDR to transmit a tone, full scale at 2.4GHz and connected Tx1 of AntSDR with Rx of PlutoSDR using cable, saw the FFT using GNURadio. Repeated the experiment with Tx2 of AntSDR connected to Rx of PlutoSDR. The power levels are approx 10dB apart with Tx1 giving out more power around -60dB.

Similarly i repeated the tests by injecting tones at Rx, the RSSI at both Rx measured around 121dB.

What conclusion can I draw from these two experiments, one mentioned in previous reply with pings and the other mentioned in this post?

Regards

Nitin