IWR6843AOPEVM: Max range in visualizer tool for people counting labs

Hello

Please note a few things

1. Each demo and config file are made in tandem and although in theory you can change the radar sensing parameters to values acceptable to device the demo code may be created with certain sensing assumptions that you may be violating

So in short please do not expect demos to work while you change parameters.

If you wish to change parameters please look at the customization guide provided  specific to the  demo and or understand the implementation and assumptions made in the demo

2. For basic fmcw parameters changes - Please use the out of box demo and chirp estimator to flush the working  and processing needs then move to other demos.

So for the changes in. Question please try these on 'out of box' demo and get them working there then people counting specific issues can be addressed

Hope this helps

We will provide follow up to this thread next week.

Please respond  next week if you do not see a response.

Thank you

Vaibhav

Hi Vaibhav,

***************************

{
    "configGenerator": {
        "createdBy": "mmWaveSensingEstimator",
        "createdOn": "2020-11-26T09:54:01.464Z",
        "isConfigIntermediate": 0
    },
    "currentVersion": {
        "jsonCfgVersion": {
            "major": 0,
            "minor": 4,
            "patch": 0
        },
        "DFPVersion": {
            "major": 1,
            "minor": 2,
            "patch": 0
        },
        "SDKVersion": {
            "major": 3,
            "minor": 0,
            "patch": 0
        },
        "mmwavelinkVersion": {
            "major": 1,
            "minor": 2,
            "patch": 0
        }
    },
    "lastBackwardCompatibleVersion": {
        "DFPVersion": {
            "major": 1,
            "minor": 1,
            "patch": 0
        },
        "SDKVersion": {
            "major": 2,
            "minor": 0,
            "patch": 0
        },
        "mmwavelinkVersion": {
            "major": 1,
            "minor": 1,
            "patch": 0
        }
    },
    "systemConfig": {
        "summary": "",
        "sceneParameters": {
            "ambientTemperature_degC": 20,
            "maxDetectableRange_m": 6,
            "rangeResolution_cm": 4.5,
            "maxVelocity_kmph": 14.4,
            "velocityResolution_kmph": 2,
            "measurementRate": 10,
            "typicalDetectedObjectRCS": 1
        }
    },
    "regulatoryRestrictions": {
        "frequencyRangeBegin_GHz": 77,
        "frequencyRangeEnd_GHz": 81,
        "maxBandwidthAllowed_MHz": 4000,
        "maxTransmitPowerAllowed_dBm": 12
    },
    "processingChainConfig": {
        "detectionChain": {
            "name": "",
            "detectionLoss": 1,
            "systemLoss": 1,
            "implementationMargin": 2,
            "detectionSNR": 12,
            "theoreticalRxAntennaGain": 9,
            "theoreticalTxAntennaGain": 9
        }
    },
    "mmWaveDevices": [
        {
            "mmWaveDeviceId": 0,
            "rfConfig": {
                "summary": "",
                "waveformType": "singleFrameChirp",
                "MIMOScheme": "TDM",
                "rlChanCfg_t": {
                    "rxChannelEn": "0xF",
                    "txChannelEn": "0x7"
                },
                "rlAdcOutCfg_t": {
                    "fmt": {
                        "b2AdcBits": 2,
                        "b8FullScaleReducFctr": 0,
                        "b2AdcOutFmt": 2
                    }
                },
                "rlLowPowerModeCfg_t": {},
                "rlProfiles": [
                    {
                        "rlProfileCfg_t": {
                            "profileId": 0,
                            "pfVcoSelect": "0x0",
                            "pfCalLutUpdate": "0x0",
                            "startFreqConst_GHz": 60,
                            "idleTimeConst_usec": 7,
                            "adcStartTimeConst_usec": 6.4,
                            "rampEndTime_usec": 94.06666666666668,
                            "txOutPowerBackoffCode": "0x0",
                            "txPhaseShifter": "0x0",
                            "freqSlopeConst_MHz_usec": 38.478970527648926,
                            "txStartTime_usec": 1,
                            "numAdcSamples": 260,
                            "digOutSampleRate": 10000,
                            "hpfCornerFreq1": 0,
                            "hpfCornerFreq2": 0,
                            "rxGain_dB": "0x1E"
                        }
                    }
                ],
                "rlChirps": [
                    {
                        "rlChirpCfg_t": {
                            "chirpStartIdx": 0,
                            "chirpEndIdx": 0,
                            "profileId": 0,
                            "startFreqVar_MHz": 0,
                            "freqSlopeVar_KHz_usec": 0,
                            "idleTimeVar_usec": 0,
                            "adcStartTimeVar_usec": 0,
                            "txEnable": "0x1"
                        }
                    }
                ],
                "rlRfCalMonTimeUntConf_t": {
                    "calibMonTimeUnit": 1
                },
                "rlRfCalMonFreqLimitConf_t": {
                    "freqLimitLow_GHz": 77,
                    "freqLimitHigh_GHz": 81
                },
                "rlRfInitCalConf_t": {
                    "calibEnMask": "0x1FF0"
                },
                "rlRunTimeCalibConf_t": {
                    "oneTimeCalibEnMask": "0x0",
                    "periodicCalibEnMask": "0x0",
                    "calibPeriodicity": 10,
                    "reportEn": 1,
                    "txPowerCalMode": 0
                },
                "rlFrameCfg_t": {
                    "chirpEndIdx": 0,
                    "chirpStartIdx": 0,
                    "numLoops": 15,
                    "numFrames": 0,
                    "framePeriodicity_msec": 4.545
                }
            },
            "rawDataCaptureConfig": {
                "rlDevDataFmtCfg_t": {
                    "iqSwapSel": 0,
                    "chInterleave": 1
                }
            },
            "monitoringConfig": {}
        }
    ]
}

Hello

Our suggestion was to respond in this week in case you dont get a reply after the first one.

Lets go through each of the things you mentioned and try and address it.

1.  Max range  calculated via estimator  tool vs 'formula' you showed doesnt match.

TI:  Max range  value for below profile  when run through fmcw equation match what TI's estimator tool shows

Profile: profileCfg 0 60 80 7 27 0 0 120 1 250 12500 0 0 30

FMCW tool (close to what estimator uses)  : ~14.0m

Your formula : 7m  -  Please check for formula to be right.  See the FMCW equiations.

2.  You have extracted values from estimator tool  and used them in the profile config:

TI:  Estimator config json you have provided  vs the profile config you have provided do not seem to match.

When in Estimator tool please check the value shown by your browsers debug console

3.  Values  from profile cfg  when loaded in the visualizer tool do not show the right max range:

TI: Please check fmcw equation    as per our computation

profile: profileCfg 0 60 7 6.4 94.0666666667 0 0 38.4789705276 1 260 10000 0 0 30
should give max range of ~35m as expected.

Thank you,

Vaibhav

Hi Vaibhav,

thanks for your support.

About your points:

1. Max range  calculated via estimator  tool vs 'formula'

In the TI document /cfs-file/__key/communityserver-discussions-components-files/1023/2860.mmwaveSensing_2D00_FMCW.pdf

I found the following formula:

Max Range =  ( Fs * c ) / ( 2 * S )

Where I think the only difference from mine " Max Range =  ( Fs * Tc * c ) / ( 4 * B )  =  ( Fs * c ) / ( 4 * S ) " is the mean of Fs:

 - for me the Fs is the is the ADC sampling frequency  and so the maximum IF frequency that is resolvable by the radar module will then be Fs/2 ( FFT property )
 

- Is it possible that Fs in TI document is like shown below?

If this second option is true, the calc becames:
Max Range =  ( Fs * c ) / ( 2 * S ) = (12500Ksps * 3*10^8) / (2 * 120 MHz/usec) = 15.625 m  <<<<< DIFFERENT FROM 14.06 m. calculated by visualizer again.


Can you explain the mismatch?

If the formula is not right, can you give me the correct one?

2. You have extracted values from estimator tool  and used them in the profile config

What is the " browsers debug console " ? Is the following one?




I also noted that if I specify the Frequency range 60 - 64 GHz in the online tool, in the exported json file, the fields "frequencyRangeBegin_GHz" and "frequencyRangeEnd_GHz" always are set to 77 and 81 GHz respectively. Can be this a mismatch cause? Consider I used the values reported in the exported json file.

Regards,

Lorenzo

Hello Amanda,

nice to meet you.

Please let me know when the online estimator will be fixed.

In the formula (2) reported in your application note

Can you explain what is fc?

Is  the SNR_det value the "SNR threshold" defined in "Allocation Parameters"? ( see "the pplcount_customization_guide.pdf" in "68xx_3D_people_counting" lab )

Can I consider the radar cross section equal to 1 if  the target is a human?

Thanks for your support.

Regards,

Lorenzo

hello

In response to your post  11-30-2020

  For #1)  For mAx range we have provded the tool so that we don't have to explain and walk through the equation.

We can add the relevant information in the future but may be  bit out scope of answering forum query.

For #2:  We were referring to debug console of the browser   :( How to : https://balsamiq.com/support/faqs/browserconsole/)

For estimator tool in  Firefox

Can  you please confirm you able to

use the estimator tool,  set the required distance and  create a chipr

use that chirp in config file for demo (see debug console step)

When you use the above config in the visualizer it shows the same

If if you  can confirm above then the original query can be considered resolved.

Thank you,

Vaibhav

IN response to  12-02-2020

Fc is usually the center frequency of the BW  for 60Ghz devices you may use any from 60 to 64GHz 

Please confirm if you are unblocked and able to move ahead with configuring the device as per your needs.

Thank you,

Vaibhav

Hi Vaibhav,

Unfortunately, I cannot tell you that all is working fine. I continue to have problems in chirp configuration using the online estimator.

Do you have a .cfg file for the visualizer tool working fine according to the parameters I showed in the estimator screenshot of my post of 11-26-2020 ?

If yes, can you share it, please?

Comparing your file with mine ( reported on my post of 11-26-2020 ) I will better understand where the errors are.

Regards
Lorenzo