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Strange frequency that emitted from i7 U660

pavelan443
Beginner
335 Views

Hello.

In my Linux based product, I noticed that there is a frequency that effects my Wi-Fi transmission.
At 5760MHz.
When I tried to look for it source with RF probe, I found that it's comes from the processor it-self.

I am using i7 U6600 processor.
There is nothing about that frequency inside the data sheet. 
But it does look like some sort of PLL clock. (see pic atached)

pavelan443_0-1636118755600.png

Does someone know what this clock might be, and if I can turn it off?

Thank you

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5 Replies
JosueO_Intel
Moderator
300 Views

Hello pavelan443,


Thank you for posting on the Intel communities. In order to have a better understanding of the issue, please share with us the following information: 


  1. Linux distribution you are using.
  2. Was it working before?
  3. When did the issue start happening?
  4. Were any changes made recently to the system?
  5. What are the effects the Wi-Fi is suffering from this?
  6. Is the frequency 5760MHz from the clock speed of the processor?


Also please download and install the Intel System Support Utility (Intel SSU):

https://www.intel.com/content/www/us/en/download/18895/26735/intel-system-support-utility-for-the-li...

Open the application and select "Everything" click on "Scan" to see the system and device information. By default, Intel SSU will take you to the "Summary View". Click on the menu where it says "Summary" to change to "Detailed View".  

Click on "Next", save the report and attach it to your response.



Regards, 


Josue O.  

Intel Customer Support Technician



pavelan443
Beginner
283 Views

Hi Josue_O_Intel, thank you for reply.

 

1. I am using " Ubuntu 16.04.5 LTS (GNU/Linux 4.4.0-131-generic x86_64)", but I notice the frequency starts to emit from the processor even if I enter the BIOS before loading the OS.

 

2. The problem was encountered during RF debugging of WIFI module that integrated to our product. By "product" I mean a closed case product that consisting from Single Board Computer (with Intel i7 U6600), and a few RF modules.

I've noticed this frequency that is reproduced in all our products. Since the case is closed, the frequency is amplified by the case resonance enclosure.  The problem can be solved by adding RF energy absorber pads to the casing.

3. The problem is was always there in different degree of magnitude, depends of casing alloy.


4. No changes are made.
As I said the problem was always there, but only now I noticed this frequency that coming from the processor.
The mechanical solution is less robust since adding the energy absorption elements to the system, increase it's weight and effect the thermal profile. So I am looking for a different approach like disabling that frequency.

 

5. The channel 153 (5765MHz) is 20MHz working near the emitted frequency of 5760MHz. So when the 5760MHz is strong it makes the WIFI module that work at 5765MHz thinks that he receives signal and prevent it to start TX. Meaning it get stuck on RX mode.

6. I looked at the Intel i7 U6600 official datasheets.
link: https://ark.intel.com/content/www/us/en/ark/products/88192/intel-core-i76600u-processor-4m-cache-up-...
As I see there is nothing regards the 5760MHz frequency, and it cannot be a multiplication of harmonic of clocks that's on the datasheet.

I use RF probe to locate the source of the disturbance, and it's the strongest when it's located on the processor it self. Of course during the measure, I disconnected all other models beside the motherboard, and the DDR, So I know for sure that it's coming from the processor.

JosueO_Intel
Moderator
271 Views

Hello pavelan443, 



Thank you for the information provided 


I will proceed to check the issue internally and post back soon with more details. 



Best regards, 


Josue O.  

Intel Customer Support Technician



JosueO_Intel
Moderator
248 Views

Hello pavelan443,


In this case, we recommend you check your BIOS settings with the system manufacturer. This is because electronic issues are handled by the BIOS configuration and in order to get assistance with it, you need to contact the OEM. 


Please check with them for possible troubleshooting at the BIOS level or for a possible warranty request. 



Best regards, 


Josue O.  

Intel Customer Support Technician



JosueO_Intel
Moderator
224 Views

Hello pavelan443,


If you need any additional information, please submit a new question as this thread will no longer be monitored.



Best regards, 


Josue O.  

Intel Customer Support Technician



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