AWR1843BOOST: Beam Forming - phase shifting

Hi,

Wajih Youssef said:

exact choice of the values {0, 0, 19 }

These are phase shifter calibration values.

I will need some time to find out how they are computed

Wajih Youssef said:

if(l_tx1phCode < 0)
l_tx1phCode = l_tx1phCode + 64 ;
if(l_tx2phCode < 0)
l_tx2phCode = l_tx2phCode + 64 ;
if(l_tx3phCode < 0)
l_tx3phCode = l_tx3phCode + 64 ;

The phase shifter has 64 steps, so when it is negative, we wrap around.

thank you

Cesar

Okay Cesar, Thank you 

Thank you

Cesar

Thank you @Cesar , I have just one last question I want to know whether the difference in phase between the tx antennas ( lambda/2) ( like in my case the AWR1843) is taken into consideration in the calculation process of the phase shift value ( using the Matlab code )

you can find the Matlab code I am talking about in this thread

e2e.ti.com/.../3230709

Please give me some time to review this

thank you

Cesar

Okay Cesar, thanks a lot 

Hello Cesar thanks for your reply, 

yes, I have seen in other threads that the code in Matlab is implementing those formulas I was just wondering whether it is taken into consideration the phase difference between the Tx2 and the two other Tx ? due to the difference in position ( Tx2 being the elevation antenna) because when I tried the beam steering sometimes I get great results from an off-angle ( for example the object is at 20 degrees and the radar detected it although the angle of the beam is at -40 degrees ) any idea? thanks 

Hi,

No, this does not take into consideration the fact that Tx2 has a different elevation.

I think there are some issues with the beamsteering demo.

I am reviewing the computation of the phase shifter coefficients.

Thank you

Cesar

Thank you, Cesar,

Looking forward to hearing from you after you've completed your review. 

Thank you

Please give me a few days

thank you

Cesar

Hi Cesar, Okay thanks 

Hello Cesar, so are there any news or updates? 

Hi Cesar, Thanks for your reply I will check it with the new script thanks a lot!  

Hi Cesar I changed the lookup table for some angles, I wanted to ask whether there should be a change in the code as well or not ? because the Matlab script generates negative values which upon building the code composer code generates the following warning : " #69-D integer conversion resulted in a change of sign

Thanks

Hi Cesar, thanks for the clarification. I have tested the beam steering though and I have yet another question, if I put an object and I steer from -60 to 60 with a 20-degree step ( -60 -40 -20 0 20 40 60) shouldn't the values read by the visualizer change when the angle change ? ( at least from positive angles to the negative ones) what I noticed is that there isn't much change neither in the coordinates of detected points nor in the signal intensity! 

Hi Cesar, I spent some time reviewing the new script you sent me and I noticed that you changed the distance d (lambda/2) which didn't take into consideration the value of lambda in the old Matlab script but I want to ask you how does this new code take into consideration the elevation of the TX2 for the calculation process ? 

thanks 

Hi,

When we enable all 3Tx we don't have elevation information any more.

thank you

Cesar

yes yes I know thanks Cesar, and just to be clear the distance between the 3 antennas is lambda right ? and the elevation between tx2 and the other two antennas is lambda/2 is this right ?