AWR1243: VCO1/VCO2 setting via pfVcoSelect

Hello Timur,

To use the 4Ghz BW you can use the 77-81Ghz band. You dont have to force select the VCO, the firmware will automatically select the VCO based on the requirement.

Also can you confirm if you are using 1243P or 2243P? 1243P is no longer supported. We suggest you use the 2243P device for cascade application and use the latest DFP available in the following page www.ti.com/.../MMWAVE-DFP

regards,

Vivek

Hello Vivek,

Thank you for quick reply!

We use 1243P devices in current applications and assembling new radar units based on 2243P already. We tried both firmware (internal) and forced VCO selections but both lead to data fade with VCO2 band used.

So you suppose such behavior due to 1243P devices?

Regards,

Timur

Hello Timur,

So you are observing the same behavior on the 2243P sensor also? Are you using the latest DFP for 2243?

Do you measured your antenna gain pattern at higher frequencies? Typically the antenna gain reduces at higher RF frequencies. There would be some drop in the TX o/p and Rx gain as well from the 1243/2243 device at higher frequencies, but that cannot explain the large drop in signal level you are seeing. I would suggest verifying your antenna gain pattern at higher RF frequencies.

Also do not use the force VCO option, just set the start frequency at 77Ghz and do a 4GHz ramp, automatically VCO2 would get selected. If you could share your detailed configuration I could review it once to verify if there is any issue in the configuration.

Regards,
Vivek

Sorry Vivek, it seams I've writen ambiguous. We've no 2243P at the moment, these units in production yet. So I didn't try this configuration on 2243P device. I just mean that we are migrating to 2243P already.

I guess this is not an antenna gain issue, we use the same antenna design as in TI cascade radar reference design (patch and stackup) and you are right there is a too large drop in signal level.

Please review used profile config:

        .profileId                    = (rlUInt16_t) 0,
        .pfVcoSelect               = (rlUInt8_t) 0,
        .pfCalLutUpdate         = (rlUInt8_t) 0,
        .startFreqConst           = (rlUInt32_t) CASCADE_RADAR_FREQ_GHZ_CONV(77),
        .idleTimeConst           = (rlUInt32_t) CASCADE_RADAR_TIME_US_TO_10NS(10U),
        .adcStartTimeConst    = (rlUInt32_t) CASCADE_RADAR_TIME_US_TO_10NS(5U),
        .rampEndTime            = (rlUInt32_t) CASCADE_RADAR_TIME_US_TO_10NS(60U),
        .txOutPowerBackoffCode = (rlUInt32_t) 0,
        .txPhaseShifter            = (rlUInt32_t) 0,
        .freqSlopeConst          = (rlInt16_t) CASCADE_RADAR_FREQ_MHZ_PER_MICRO_S_SLOPE_CONV(65U),
        .txStartTime                = (rlInt16_t) CASCADE_RADAR_TIME_US_TO_10NS(0U),
        .numAdcSamples        = (rlUInt16_t) (256U),
        .digOutSampleRate     = (rlUInt16_t) 5000, /* Kilo Samples per second */
        .hpfCornerFreq1          = (rlUInt8_t) RL_RX_HPF1_175_KHz,
        .hpfCornerFreq2          = (rlUInt8_t) RL_RX_HPF2_350_KHz,
        .txCalibEnCfg              = (rlUInt16_t) 0,
        .rxGain                         = (rlUInt16_t) 30

Regards,

Timur

Hello Timur,

Are you having multiple TX ON at the same time ? can you keep just 1TX ON of just one of the device? Are you seeing the same behavior on all the RXs?

Regards,

Vivek

Only one TX ON at the same time. We've done such experiment 1 TX ON just 1 device - the same behavior on the all RXs.

Regards,

Timur

Hello Timur,

Can you share your board schematics?

Regards,

Vivek

Hello, Vivek

Thank you Vivek for your considerate concern! In general this is TI reference design, but I wouldn't like to post it on the forum. Can you advice a private way?

Regards

Timur

Hello Timur,

I have sent you a friend request for private communication. 

Can you let us know the DFP version you are using ? Are you observing the same behavior on both master and slave devices? Do you have capability to look at the TX o/p externally? 

Regards,

Vivek

We use mmwave_dfp_01_02_00_00. Both master and slave devices have the same behavior. Unfortunately we can't look at the TX o/p externally, but if the signal band is within VCO1 band all data is good.

Thank you

Timur

Hello Timur,

Can you configure the master device in single chip mode instead of master mode?  Use only the master device , 1Tx. I suspect the 20Ghz LO signal level is very low.

Regards,

Vivek

Hello, Vivek.

Thank you for help.

I've tried your suggestion and indeed in single chip mode data apear. Is there a monitor function returning a 20GHz signal level  recieved by master/slave chip?

Regards,

Timur