Hi, TI team,
Recently I'm studying the Obstacle Detection demo codes from toolbox_lab0004 for AWR1642-ODS. Since it lacks of detail description documents for these demo codes, some parts of the behavior still couldn't be understood by myself. Thus, the questions are list down below:
1. ODSDEMO_dopplerProc (in Odsdemo_doppler.c): At the end of doppler FFT process, what is the purpose and meaning of "generate the rotation"?
Is this step become the pre-process of the following ODSDEMO__aoaEstBF2D process?
// generate the rotation
if (doppMimoFlag == 1)
{
float re, im, phi;
phi = -PI*(float)(k)/(float)(fftSize);
re = (float) cos(phi);
im = (float) sin(phi);
rotation = _ftof2(re, im);
}
offset = 0;
// Apply rotation, output format: imaginary first, real second
for (antIdx = 0; antIdx < nAnt; antIdx++)
{
if ((doppMimoFlag == 1) && antIdx >= (nAnt >> 1))
{
tempIn = _ftof2(fftOutPtr[offset + 2 * maxIndex], fftOutPtr[offset + 2 * maxIndex + 1]);
tempIn = _complex_mpysp(rotation, tempIn);
_amem8_f2(&dopplerProcOut->outBuffer[2 * antIdx]) = tempIn;
}
else
{
_amem8_f2(&dopplerProcOut->outBuffer[2 * antIdx]) = _ftof2(fftOutPtr[offset + 2 * maxIndex], fftOutPtr[offset + 2 * maxIndex + 1]);
}
offset += (fftSize << 1);
}
2. How does the 2D-FFT procedure exactly do and operate in ODSDEMO__aoaEstBF2D function?
Since the overall 8 virtual antennas were scheduled as different number at vertical or horizontal. (i.e. 1/1/3/3 scheduled as a 4-by-3 array.)
I'm looking forward for your guidance.
Many thanks.
Shihyu.
