I have been trying to do VNA-ish operation with libbladeRF and C code. So far, I could synchronise tx and rx with timestamp and obtained magnitude looks ok. However, I cannot retrieve phase.
What I do at a frequency is: referring to some earlier posts, tx and rx frequencies are set at a few MHz apart. Sampled waveform is Fourier transformed and a complex number is extracted at the frequency bin, which is calculated from the frequency offset of tx and rx.
I found that the phase of sampled waveform that oscillating at the beat frequency is different each time as shown in below.
This is what I can get with 1 MHz beat frequency, 20 MHz sampling rate, and repeated 70 times. I expected all the lines to be overlapped.
Also there is a break later in the sampled waveform where phase also changes, although I made tx waveform for full 16384 samples long, as
Would be really helpful and appreciated if some could help me out on this.
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