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Center Freq in bladeRF-cli Vs Bin file

Posted: Sun Jul 31, 2022 10:38 am
by dkelly
Hope this is not a dumb question, but...

When you "set frequency" via bladeRF-cli, what are you actually doing? Does this, along with "set bandwidth," set up filters in the RF front end?

The reason I ask is the following. I can "set frequency" via bladeRF-cli to 920MHz, but then TX using a bin file where I've created an IQ signal at 915MHz. When I enable transmit, I see only the 915MHz signal on the signal analyzer. So my guess has been that "set frequency" is really just setting up the filters in the RF front end to allow signals near that "set frquency" freq to be transmitted or received.

Am I guessing correctly, or is there more to it?

Thx much!

Re: Center Freq in bladeRF-cli Vs Bin file

Posted: Mon Aug 01, 2022 6:56 pm
by robert.ghilduta
Set frequency sets up the AD9361's LO. Please note that TX1 and TX2 share one LO. So if TX1 is set to one center frequency but TX2 to another, TX1 will by definition be moved to the new frequency.

Bandwidth, when doing "set bandwidth" configures the baseband Low Pass Filter. It should generally be smaller than the sampling rate to limit aliasing.

Re: Center Freq in bladeRF-cli Vs Bin file

Posted: Wed Aug 03, 2022 7:52 am
by dkelly
Thx!