I'm trying to set RX1 and RX2 to different frequencies, so that I can receive both Uplink and Downlink I/Q data for different LTE bands. For now I'm just using BladeRF-cli.
However, when I go to set RX2, it sets both RX1 and RX2 to that frequency. Any ideas about what I'm doing wrong?
Setting different frequencies for RX1 and RX2
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Re: Setting different frequencies for RX1 and RX2
This is not possible. The two RX ports share a common LO. Likewise for the two TX ports.
One might then wonder what is the purpose of that. There are many applications that use multiple "spigots" (MIMO) tuned to the same frequency. Because there are multiple, sometimes smaller, antennas, they can work together to provide significant improvements to gain, interference reduction, and data throughput. MIMO also lets you do some unique things like beamforming, which cannot be done with a single antenna. There's a decent introductory Wikipedia page on the topic if you are interested in learning more about it.
One might then wonder what is the purpose of that. There are many applications that use multiple "spigots" (MIMO) tuned to the same frequency. Because there are multiple, sometimes smaller, antennas, they can work together to provide significant improvements to gain, interference reduction, and data throughput. MIMO also lets you do some unique things like beamforming, which cannot be done with a single antenna. There's a decent introductory Wikipedia page on the topic if you are interested in learning more about it.
Electrical Engineer
Nuand, LLC.
Nuand, LLC.
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Re: Setting different frequencies for RX1 and RX2
Thanks for your response!
So is there a way to make a setup like this work with the BladeRF 2.0? https://github.com/Nuand/bladeRF/tree/m ... i/sync_trx
I had it working previously with two x40s. Thanks
So is there a way to make a setup like this work with the BladeRF 2.0? https://github.com/Nuand/bladeRF/tree/m ... i/sync_trx
I had it working previously with two x40s. Thanks
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Re: Setting different frequencies for RX1 and RX2
The bladeRF2 supports trigger inputs/outputs and should work the same as bladeRF1. I believe you would still need two bladeRFs. You might be able to get away with pairing the bladeRF2 with one of your existing bladeRF x40s.
Electrical Engineer
Nuand, LLC.
Nuand, LLC.
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Re: Setting different frequencies for RX1 and RX2
Thanks for the response, that's good to hear. I do have two xA4s so that's fine. I'm guessing I have to modify the trigger pin commands, and the clock commands in the scripts from that github link. So j71-4 should be j51-1 for the 2.0 boards. Just need to figure out how to set the clocks as out/in - what's the equivalent for "smb_mode" with the xA4s?
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Re: Setting different frequencies for RX1 and RX2
If you're using the bladeRF-cli, then to enable/disable the UFL clock output (J92):
and to change the 38.4 MHz source (onboard VCTCXO or external via U.FL (J93)):
If using an external clock, it should be within 10 kHz (or 100 kHz? I forget..) of 38.4 MHz, otherwise the FX3's PLL may unlock and you'll drop the USB connection. The PLLs on the FPGA may also unlock, causing it to reset itself.
Code: Select all
set clock_out enable|disable
Code: Select all
set clock_sel external|onboard
Electrical Engineer
Nuand, LLC.
Nuand, LLC.