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stevecrmParticipant- This reply was modified 6 years, 7 months ago by
stevecrm.
stevecrm September 11, 2018 at 9:36 am in reply to: Recording Raw IQ Samples – Suspiciously low values? //php bbp_reply_id(); ?>
For reference these are my capture settings
`bb_api.bbConfigureCenterSpan(id, 70000000, 4.0e6); //center hz, span hz
bb_api.bbConfigureLevel(id, -20.0, bb_api.BB_AUTO_ATTEN);
bb_api.bbConfigureGain(id, bb_api.BB_AUTO_GAIN);
bb_api.bbConfigureIQ(id, bb_api.BB_MIN_DECIMATION, 4.0e6); //bandwidth hz
stevecrmParticipantstevecrm August 22, 2018 at 10:53 am in reply to: Pull IQ Samples To Make Constellation Plot (API) //php bbp_reply_id(); ?>
When I pull IQ samples are they already shifted down to baseband? For instance when I sample my 70MHz signal at 40Msamp/s I believe I should have 27MHz of instantaneous bandwidth. Has that 27MHz around 70MHz been shifted to 27MHz around 0Hz?
stevecrmParticipantstevecrm August 21, 2018 at 4:55 pm in reply to: Pull IQ Samples To Make Constellation Plot (API) //php bbp_reply_id(); ?>
Thanks for the quick response!
I realize there’s a lot more than just plotting the samples, first of all my signal is 1.86Msym/s and I pulled points at 40, so there’s some intense re sampling needed.
Before going through with the rest of the work I was concerned about how low my samples were compared to the stated range.
Either way it’s going to be fun to try! It’s one of those things I had a textbook knowledge of, going to be fun actually try coding it!
Thanks for the link!!
stevecrmParticipantstevecrm August 21, 2018 at 12:13 pm in reply to: Pull IQ Samples To Make Constellation Plot (API) //php bbp_reply_id(); ?>
I’ve attached a picture of the data I got from my capture
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