Other Parts Discussed in Thread: DCA1000EVM
Tool/software:
Recently I have been recreating the plots from mmWave's post-processing in Python, during which I noticed that the range within the MATLAB (,i.e. post processing) plots seems to be off. It turns out that this discrepancy is due to the post-processing somehow using a different bandwidth than what is shown in mmWave Studio. Remarkably, though, the frequency slope is the same in both cases.
Please take a look at these pictures. In mmWave Studio, the frequency slope was set to 50 MHz/us, which yields a bandwidth of 3001 MHz. The post-processing reports the same frequency slope but a bandwidth of only 1280 MHz. Interestingly, though, the post-processor reports the same characteristic chirp times that are seen in mmWave Studio, in this case, T_idle = 100 us and T_ramp = 60 us. Using T_ramp and f_slope, we get B = 3000 MHz. So where does the post-processing get this value of 1280 MHz?
Please note that the bandwidth value within the post-processing is used for the calculation of the range. For example, in the range-Doppler plot for N_samples = 256:
- At 3000 MHz, the range would be:
256 * 3e8 / (2 * 3e9) = 12.8 m - At 1280 MHz, the range would be:
256 * 3e8 / (2 * 1.28e9) = 30 m
The latter one is what can be seen on the range-Doppler plot from the post-processing.
Does anyone know why this mismatch occurs? Any insights would be greatly appreciated!
(The data were gathered with an AWR1843BOOST in conjunction with the DCA1000EVM)
