IWR1443BOOST: The problem of phase transition changes of different receiving antennas

Hi

Thanks for your query. Please allow us a couple of days to respond.

Regards

HI, there:

My understanding is the TX and RX gain will decrease as temperature increases.  So, I can imagine total gain reduced during this measurement.  Please track the gain and phase of your target at the same time.  At the same time, I would recommend using a point target (such as corner reflector) to simplify the problem.   

Please let me know how you calculate the phase and please share the setup picture and zero Doppler output plots if possible. 

Best,

Zigang

This is the phase measured for 11 hours, why is the upward and downward trend of the four antennas inconsistent? The target is not moving, why is it going up and down?

I've changed the target to an angular reflector, but why does the phase of 128chirps have an upward trend, and the amplitude has a downward trend,

Hi, there:

As I said, the gain reduces with the temperature.  I am not sure about the phase.    After changed to corner reflector, the level of amplitude and phase drifting looks really small to me.   Let me know if this is still a concern to you. 

Best,

Zigang 

But this is just one data, I have collected it more than ten times in a row, and its changes are quite significant. Moreover, the phase change of antenna 4 is significantly different from other antennas.

Please send me the worst results with corner reflector.

Best,

Zigang 

Why do they go further and further, they don't correspond to the same phase change value？

tongxin

HI, Tongxin:

Do you mean the figure you shown below is the phase change within the frame? And the second figure below is the phase change cross frames?

Best,

Zigang

yes,the second is some hours

HI, there:

Across chirps within a frame:

• Amplitude drop is expected due to thermal settling. Phase typically shows an upward trend. This is expected.

In the long term stability test:

• The phases of 4 receive chains track pretty well in the first half of the test. Then, something has happened to the test setup. The phases are decreasing in the second half of the test. Is the ambient temperature being reduced here?
• Is the test performed on IWR1443 boost or another customer made platform?
• Do you have the die temperature readouts when the 13.5 hours is performed?

Best, 

Zigang,

Hello, this is the case for ambient temperature, ambient humidity, and phase. Measured with IWR1443 Boost. How do I read the temperature of the board? Want to read four different antennas?
tongxin

Hi, Tongxin:

What is the test condition difference between this test and previous test?  

In this results, you only showed two antennas. Are all antenna have the same phase change? 

Another suggest from our system engineer is to change the target IF frequency, which equals freqSlope*2*targetRange/300. Right now, you have 66.5*2*0.748/300 = 330K, which is too close to the High pass filter corner frequency.  Can you adjust the slope or range?  so that the target falls into higher IF frequency.  

How did you get the temperature reading that shows in the figure?

Best,

Zigang

Hello, I changed the position of the target, and it still has this change.

Hello, does the temperature change of the radar board affect the phase measurement of the four antennas? If so, how might it have been affected.

Hello, to add to that, we have deactivated the on-board crystal oscillator and introduced an external clock source that is not affected by temperature.

Best,

Tongxin.

HI, Tongxin:

Can you summarize what is the difference between these two results?  It is still not clear to me?

By the way, in order to record the board temperature, you can enable the following two LUA API

You should be able to see the temperature in the CalibrationReport.txt, looks like below.  Temperature is highlighted in yellow

[14/10/2024 18:57:37] DeviceId [1] RunTimeCalibReport: 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 262144, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 49, 0, 762090, 15

Best,

Zigang

The two graphs are the same measurement, but in Figure 2 I only drew the phases of the two antennas. Hello, are you Chinese, I feel like you are by looking at your name

HI, there:

Can you give me an update on the latest test results?  The figure below shows consistent phase change cross all antennas.   What is your main concern?  How it affect your applications?

Yes, I can read Chinese.  If you have to, you can write in Chinese and then include the google translate below that. 

Best,

Zignag

I am currently using phase measurement to measure small displacements. My current small displacement is about 5 °, but my small displacement is very slow. I cannot get rid of this superimposed change, which affects my measurement accuracy. My teacher asked me to provide long-term stability measurements, but I have been stuck here all along

HI, there:

Usually in our FMCW chirp-based application, we are looking at the range/Doppler/angle information from one frame of data or several frames of data.  There is not such a stability requirement in our datasheet.  

Let me know if the datasheet shows differently.  I will also try to reach the system team to confirm and I get back to you next week. 

Best,

Zigang