IWR6843ISK: Extract angle FFT input

Kazu Hira

Part Number: IWR6843ISK

Hi,

I want to extract azimuth angle FFT input in OOB demo.

Here, angle FFT input mean the result finished to process doppler and gain/phase compensation.

I have extracted angle FFT input by below additional code('AoAProcDSP_processMultipleVirtualAntennas' in 'aoaprocdsp.c').

/* RX channel gain/phase offset compensation. */
AoAProcDSP_rxChanPhaseBiasCompensation(&aoaDspObj->dynLocalCfg.compRxChanCfg.rxChPhaseComp[0],
DPParams->numVirtualAntAzim + DPParams->numVirtualAntElev,
&res->angleFftIn[0],
&res->angleFftIn[0]);

/*Original code*/

static void myfunc(const int32_t * v_in){

double _Complex k1,k2,k3,k4,k5,k6,k7,k8;

k1 = v_in[0] + v_in[1]*I;
k2 = v_in[2] + v_in[3]*I;
k3 = v_in[4] + v_in[5]*I;
k4 = v_in[6] + v_in[7]*I;
k5 = v_in[8] + v_in[9]*I;
k6 = v_in[10] + v_in[11]*I;
k7 = v_in[12] + v_in[13]*I;
k8 = v_in[14] + v_in[15]*I;

}

myfunc(&res->angleFftIn[0]);

But it seems that this is not result I want.

I think input of azimuth angle fft has 'cmplx32ImRe_t ' type.

So, all I have to do is extracting every 32bytes (alternately real part and imaginary part).

Please let me know if I have any mistakes.

I show my environment for reference.

[Radar]

IWR6843ISK

[SDK]

mmwave_sdk_03_03_00_03

[Loading image ]

‘…\ti\mmwave_sdk_03_03_00_03\packages\ti\utils\ccsdebug\xwr18xx_ccsdebug.bin’

[Demo]

'...\ti\mmwave_industrial_toolbox_4_2_1\labs\out_of_box_demo\68xx_mmwave_sdk_dsp'

[CCS]

8.3.1.00004

[config]

sensorStop

flushCfg

dfeDataOutputMode 1

channelCfg 15 5 0

adcCfg 2 1

adcbufCfg -1 0 1 1 1

profileCfg 0 60 7 8 60 131586 0 60 1 512 10000 0 0 30

chirpCfg 0 0 0 0 0 0 0 1

chirpCfg 1 1 0 0 0 0 0 4

frameCfg 0 1 28 0 33.3 1 0

lowPower 0 1

guiMonitor -1 1 0 0 0 0 0

cfarCfg -1 0 2 8 4 3 0 15 1

cfarCfg -1 1 0 4 2 3 1 15 1

multiObjBeamForming -1 1 0.5

clutterRemoval -1 0

calibDcRangeSig -1 0 -5 8 256

extendedMaxVelocity -1 0

bpmCfg -1 0 0 1

lvdsStreamCfg -1 0 0 0

compRangeBiasAndRxChanPhase 0.0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0

measureRangeBiasAndRxChanPhase 0 1.5 0.2

CQRxSatMonitor 0 3 5 121 0

CQSigImgMonitor 0 127 4

analogMonitor 0 0

aoaFovCfg -1 -90 90 -90 90

cfarFovCfg -1 0 0 8.92

cfarFovCfg -1 1 -1 1.00

sensorStart

Regards,

Kazuki

over 5 years ago

0 Nitin Sakhuja over 5 years ago

TI__Mastermind 30405 points

Hi Kazuki-san,

The input to the angle FFT is an array of type cmplx32ReIm_t as shown below from aoaprocdsp.h.

    /*! @brief      Pointer for angle (azimuth and elevation) FFT input buffer.    \n
                    Size: sizeof(cmplx32ReIm_t) * DPU_AOAPROCDSP_NUM_ANGLE_BINS\n
                    Byte alignment Requirement = @ref DPU_AOAPROCDSP_BUFFERS_BYTE_ALIGNMENT
     */
    cmplx32ReIm_t   *angleFftIn;

This datatype is defined in packages\ticommon\sys_types.h as below. So 32 bytes for real data, followed by 32 bytes for complex data.

/*! @brief  Complex data type. This type of input, (first real than
 * imaginary part), is required for DSP lib FFT functions */
typedef struct cmplx32ReIm_t_
{
    int32_t real; /*!< @brief real part */
    int32_t imag; /*!< @brief imaginary part */
} cmplx32ReIm_t;

So you should be able to save this buffer in the following code from CCS memory window for your experiment, but need to use the same data type i.e. cmplx32ReIm_t for interpreting it.

            /* RX channel gain/phase offset compensation. */
            AoAProcDSP_rxChanPhaseBiasCompensation(&aoaDspObj->dynLocalCfg.compRxChanCfg.rxChPhaseComp[0],
                                                   DPParams->numVirtualAntAzim + DPParams->numVirtualAntElev,
                                                   &res->angleFftIn[0],
                                                   &res->angleFftIn[0]);

            /* Save elevation symbols before doing Azimuth FFT.*/
            if(DPParams->numVirtualAntElev > 0)
            {
                memcpy((void*)&elevationSymbols[0],
                       (void*)&res->angleFftIn[DPParams->numVirtualAntAzim],
                       DPParams->numVirtualAntElev * sizeof(cmplx32ReIm_t));
            }

            /* Zero padding */
            memset((void *) &res->angleFftIn[DPParams->numVirtualAntAzim], 0,
                   (DPU_AOAPROCDSP_NUM_ANGLE_BINS - DPParams->numVirtualAntAzim) * sizeof(cmplx32ReIm_t));

            /* 3D-FFT (Azimuth FFT) */
            DSP_fft32x32((int32_t *)res->angleTwiddle32x32,
                         DPU_AOAPROCDSP_NUM_ANGLE_BINS,
                         (int32_t *) &res->angleFftIn[0],
                         (int32_t *) &azimuthFftOut[0]);

Regards

-Nitin

0 Kazu Hira over 5 years ago in reply to Nitin Sakhuja

Intellectual 680 points

Hi nitin-san,

Thank you as always.

I have already verified by data type you suggested.

But the results were same.

/*sample code*/

static void myfunc(const cmplx32ReIm_t * v_in){

double _Complex k1,k2,k3,k4,k5,k6,k7,k8;

k1 = v_in[0].real + v_in[0].imag*I;
k2 = v_in[1].real + v_in[1].imag*I;
k3 = v_in[2].real + v_in[2].imag*I;
k4 = v_in[3].real + v_in[3].imag*I;
k5 = v_in[4].real + v_in[4].imag*I;
k6 = v_in[5].real + v_in[5].imag*I;
k7 = v_in[6].real + v_in[6].imag*I;
k8 = v_in[7].real+ v_in[7].imag*I;

}

myfunc(&res->angleFftIn[0]);

I'm concerned these are not input data for angle FFT.

I want to extract only azimuth direction inputs and I understand it matches consecutive numbers from '0' to '7'.

Is my understanding correct?

Regards,

Kazuki

0 Nitin Sakhuja over 5 years ago in reply to Kazu Hira

TI__Mastermind 30405 points

Kazuki-san,

This is the input to the angle FFT and each symbol represents the Doppler FFT hypotheses for azimuth virtual antenna n (n = 0 - 7) after gain, phase and Doppler compensation.

You can see that the DSP_fft32x32 function is called on this array to perform the FFT. I'm not sure what result are you expecting (or what verification you are trying to perform), but please note a couple of things:

1. The array is zero padded to length DPU_AOAPROCDSP_NUM_ANGLE_BINS before sending it for FFT.

2. Again, not sure what about the objective of your verification and what values are you expecting in this array so please clarify.

Regards

-Nitin

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IWR6843ISK: Extract angle FFT input