IWR1843: How can I detect the interference between sensors working in different frequence bands?

Jun Fang

Part Number: IWR1843

Hi,

I'm using out-of-box demo of mmwave_sdk_03_06_00_00 in IWR1843.

Assume I have two sensors woking in 80-81G and 77-79G with the same slope respectively. It seems the interference doesn't happen according to my experiments. I think there should be some filter which checks the IF freqency <= 1G.

There is a customer requirment about using the 77-79G sensor to detect the 80-81G sensor based on interference, I think it can be achieved by turn off the IF frequency checking.

Hence, where are codes related to the IF frequency checking?

Thanks.

over 1 year ago

0 Josh Dye over 1 year ago

TI__Genius 12801 points

Hi,

Please allow me a day to check on this and get back to you with a response.

Best Regards,

Josh

0 Jun Fang over 1 year ago in reply to Josh Dye

Prodigy 170 points

Any update? Thanks.

0 Josh Dye over 1 year ago in reply to Jun Fang

TI__Genius 12801 points

Hi,

My apologies for the delayed response. Please see this thread on the same topic: https://e2e.ti.com/support/sensors-group/sensors/f/sensors-forum/1166970/iwr6843-configuring-if-bandpass-filter-on-the-iwr6843

Additionally, you may be interested in this application note and training video on interference detection and mitigation with TI mmWave devices.

Best Regards,

Josh

0 Jun Fang over 1 year ago in reply to Josh Dye

Prodigy 170 points

Hi, Thanks for your reply.

I have read the thread and the interferece related document. It says that the parallel interference cannot happen bewteen two radars with differnt IF bandwith even the two chirps happen in almost the same time.

I want to know the details of avoiding interference between radars with different IF bandwith. Where is the filter? Is it after the ADC sampling? If Yes, I can turn off the filter to make the interference happen.

To make it clear. Suppose two radars woking in the same slope, radar1 is in the 77G-78G, radar2 is in 78G-79G. Assume radar2 recieves radar1's signal in the chirp time. Then the IF frequency is greater than 1G, which should be filtered since the IF frequency should be less than 1G. My question is when does the fitler happen, and where are related codes and configurations.

Thanks.

+1 Josh Dye over 1 year ago in reply to Jun Fang

TI__Genius 12801 points

Hello,

Please accept my sincerest apologies for the delayed response. I believe I misunderstood the question before so I'm sorry for the confusion.

Jun Fang said:
Where is the filter? Is it after the ADC sampling?

The image below is from the IWR1843 datasheet. The IF filtering occurs before ADC conversion.

The cutoff frequencies are programmable in discrete steps. Information regarding configuring the cutoff frequencies can be found in the mmWave SDK User Guide as seen below.

Best Regards,
Josh

0 Jun Fang over 1 year ago in reply to Josh Dye

Prodigy 170 points

Thanks for your reply. I have solved the problem.

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IWR1843: How can I detect the interference between sensors working in different frequence bands?