AWR2243: Does the AWR2243 "digOutSampleRate" influence the MIPI CSI-2 output

Dear team,

We are using a cascaded radar with 4 AWR2243 chips. We encountered some problems when debugging the chirp profile parameters.

The time of chirp we are using is 34e-6 second and slope is 13e12 Hz/s, the number of ADC samples is 500 complex points,

we made profile parameters below:

#define CHAINS_CASCADE_RADAR_RADAR_HEIGHT   (3U)             //# Periodicity
#define CHAINS_CASCADE_RADAR_PROFILE1_RADAR_WIDTH   (500U)   //# ADC Samples
#define CHAINS_CASCADE_RADAR_SAMPLING_RATE_KSPS     (18500U) //#digOutSampleRate
#define CHAINS_CASCADE_RADAR_IDLE_TIME_IN_US        (2U)     //# idleTimeConst
#define CHAINS_CASCADE_RADAR_SLOPE_MHZ_PER_US       (13U)

rlProfileCfg_t gChains_cascadeRadarProfileArgs[] = {
{
.profileId             = (rlUInt16_t) 1,
.pfVcoSelect           = (rlUInt8_t) 0,
.pfCalLutUpdate        = (rlUInt8_t) 0,
.startFreqConst        = (rlUInt32_t) CHAINS_AR1243_FREQ_GHZ_CONV(80),
.idleTimeConst         = (rlUInt32_t) CHAINS_AR1243_TIME_US_TO_10NS(CHAINS_CASCADE_RADAR_IDLE_TIME_IN_US),
.adcStartTimeConst     = (rlUInt32_t) CHAINS_AR1243_TIME_US_TO_10NS(1U),
.rampEndTime           = (rlUInt32_t) CHAINS_AR1243_TIME_US_TO_10NS(32U),
.txOutPowerBackoffCode = (rlUInt32_t) 0,
.txPhaseShifter        = (rlUInt32_t) 0,
.freqSlopeConst        = (rlInt16_t) CHAINS_AR1243_FREQ_MHZ_PER_MICRO_S_SLOPE_CONV(CHAINS_CASCADE_RADAR_SLOPE_MHZ_PER_US),
.txStartTime           = (rlInt16_t) CHAINS_AR1243_TIME_US_TO_10NS(0U),
.numAdcSamples         = (rlUInt16_t) CHAINS_CASCADE_RADAR_PROFILE1_RADAR_WIDTH,
.digOutSampleRate      = (rlUInt16_t) CHAINS_CASCADE_RADAR_SAMPLING_RATE_KSPS,
.hpfCornerFreq1        = (rlUInt8_t) RL_RX_HPF1_175_KHz,
.hpfCornerFreq2        = (rlUInt8_t) RL_RX_HPF2_350_KHz,
.txCalibEnCfg          = (rlUInt16_t) 0,
.rxGain                = (rlUInt16_t) 30
}
}

The radar boot up normally, but then we encountered problems at the receiver end.

The data transfer is based on the MIPI interface and the radar data stream could not be read properly when we used the above parameters.

However, the receiver could read radar data stream normally when "numAdcSamples = 250" and "CHAINS_CASCADE_RADAR_SAMPLING_RATE_KSPS =10000".

The questions are:

1. How do we decide the value of "digOutSampleRate" , "adcStartTimeConst", "idleTimeConst", according to the number of samples amd time of the chirp we need?

2. Does the value of "digOutSampleRate" influence the MIPI output ?

3. How could we receive the data stream when numAdcSamples = 500 ?

Thanks a lot !

Best,

Jim