Hi Marcus, Thanks for the explanation, so I have to prepare the I/Q samples in my program. Furthermore, can I understand the send() function will multiplex/transform the I/Q samples to final REAL baseband waveform samples. Then the USRP hardware simply multiply amplitude of each REAL sample to the carrier frequency and transmit? WANG Cui
From: Marcus D. Leech <[email protected]> Sent: Thursday, August 19, 2021 10:43 AM To: [email protected] Subject: [USRP-users] Re: How to prepare I/Q sample for tx_streamer On 2021-08-18 10:31 p.m., ?? WANG Cui wrote: Hi, Maybe I am asking a newbie question. When use tx_streamer::send() function to send signal, the required format is I/Q samples (say otw_format = sc16). I understand should provide I/Q samples buffer in arguments. I am wondering for the I/Q samples, should I provide binary values buffer (e.g. I: 1, -1, 1..., Q: -1, 1, -1...), then the USRP firmware will modulate the binary values to specific Cos/Sin waves? Or I should do the Cos/Sin modulation in my program (e.g. I: 0, -.001, 0.002..., Q: -1, 0.999, -0.998...) before pass the buffer send() function? I searched the documents, but can't find answer, thanks in advance for explanation, WANG Cui _______________________________________________ USRP-users mailing list -- [email protected]<mailto:[email protected]> To unsubscribe send an email to [email protected]<mailto:[email protected]> The whole point of an SDR is that it doesn't have any pre-defined notion of what modulation techniques are used, etc. That's entirely up to you. You're sending a complex-baseband representation of *waveforms*. The UHD library is NOT a DSP library. It is a device-interface library. If you need something higher-level, there's Gnu Radio (http://www.gnuradio.org) or even MATLAB. But SDR radios in general don't have any built-in modulation. They want sampled baseband waveforms.
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