I am not expert in this, do you mean if sample in real format, we must double the sample rate, to contain both I phase and Q phase information? In my application, I just sample at baseband digital code rate (Nyquist Freq), and seems it works well when transmit. And when I convert it into I/Q, it just doubled the size, but seems doesn’t bring more benefit? Is there good article can help me to clarify this concept? :)
From: Marcus D Leech <[email protected]> Sent: Tuesday, April 13, 2021 12:08 PM To: 王璀 WANG Cui <[email protected]> Cc: [email protected] Subject: Re: [USRP-users] How to tx s16 file with tx_samples_from_file No. A real-sampled signal would Need to be sampled at twice the notional bandwidth. So the data rate is the same. Sent from my iPhone On Apr 12, 2021, at 11:59 PM, 王璀 WANG Cui <[email protected]<mailto:[email protected]>> wrote: That make sense, I guess I would modify it to accept more format. However, for the hardware side, it accept only Complex OTW format, which means it need double bandwidth from host (I am using B210, USB3). When transmit high sample rate signal, it is very easy to underflow. If we can upgrade firmware to handle format conversion on hardware level, it will ease a lot on host computing resource and USB/NIC bandwidth and performance. Thanks! From: Marcus D Leech <[email protected]<mailto:[email protected]>> Sent: Tuesday, April 13, 2021 11:45 AM To: 王璀 WANG Cui <[email protected]<mailto:[email protected]>> Cc: [email protected]<mailto:[email protected]> Subject: Re: [USRP-users] How to tx s16 file with tx_samples_from_file The tx_samples_from_file application is just an example application. You are free to modify it to meet your needs, including converting real-samples data to complex baseband data The hardware, however, supports complex baseband data, In either sc16 or sc8 format “over the wire”. The host software (whether that’s the tx_samples_from_file example code or your own) is free to accept and convert files into the baseband format accepted by the radio hardware. Sent from my iPhone On Apr 12, 2021, at 10:08 PM, 王璀 WANG Cui <[email protected]<mailto:[email protected]>> wrote: Thanks for reply. However for RF signal, IQ Complex signal double the file size, which is quite inconvenient, it will be best that USRP can natively support such format. (Even sometimes RF signal is in 4-bit, 1 bit format, and convert to I/Q will be more than 10 times larger...) From: Marcus D Leech <[email protected]<mailto:[email protected]>> Sent: Tuesday, April 13, 2021 09:44 AM To: ?? WANG Cui <[email protected]<mailto:[email protected]>> Cc: [email protected]<mailto:[email protected]> Subject: Re: [USRP-users] How to tx s16 file with tx_samples_from_file Complex baseband is the natural format for this stuff. If you have real-sampled data you’ll have to convert it into complex baseband first. Sent from my iPhone On Apr 12, 2021, at 9:32 PM, ?? WANG Cui <[email protected]<mailto:[email protected]>> wrote: Hi, When I try tx_samples_from_file example, looks like it only take Complex data format. However I have signal file in RF direct sample format (each data element represent a sample value), say it is “s8” or “s16” format as defined in UHD term. I wonder how can I transmit such file? Or must I convert it into Interleaved I/Q (Complex) format? Thanks in advance, iucganw _______________________________________________ USRP-users mailing list -- [email protected]<mailto:[email protected]> To unsubscribe send an email to [email protected]<mailto:[email protected]>
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