Inband Image Frequency

[Lynette Sandoval]

Hello Nordic,

       I have seen a couple of your reports and I am not sure how to read the inband image frequency. You have put frequencies in there (I thought values should be between -5 to 5 ).

Here is an example of one and I have attached another one. Please let me know how to read these and how to determine the values for testing.  nRF52810-QFAA_BLE_5.0_Conforma.pdf

Thank you,

                 Lynette

[Andreas]

Hi,

 

Relative to the carrier, it is -2 MHz for 1Mbps, -4 MHz for 2 Mbps.

 

Best regards,

Andreas

[Lynette Sandoval]

Hi Andreas,

        Sorry which IXIT are you talking about? Are both -2MHz for 1Mbps and -4MHz for 2Mbps? For future when there are frequencies in the inband image section are they usually -2 and -2?

Thanks,

     Lynette

[Andreas]

Hi Lynette,

 

I am referring to the IXIT proforma which you linked. This applies to all NRF52 devices.

 

RF-PHY:P1:1	-2
RF-PHY:P1:2	-2
RF-PHY:P1:3	-2
RF-PHY:P11:1	-4
RF-PHY:P11:2	-4
RF-PHY:P11:3	-4

 

The attachment simply seems to specify this as 'With TX on x MHz, what is the inband image frequency', x = 2406 (low), 2440 (mid), 2476 (high).

 

Best regards,

Andreas

[Lynette Sandoval]

Thank you for the information. 

[Lynette Sandoval]

Hi Andreas,

            Sorry last question. Is it still -2 for 1MBS and -4 for 2MBS for nRF51822?

Thank you,

         Lynette

[Andreas]

Hi Lynette,

 

nRF51 series is a different architecture, so the inband image frequency is different. It does not support 2Mbps BLE, so only 1 Mbps applies:

• Low 1Mbps: +4 MHz
• Mid 1Mbps: +4 MHz
• High 1Mbps: +4 MHz

 

Best regards,

Andreas

[Lynette Sandoval]

Thank you. And that is for all NRF51 that those inband image frequency applies? 

[Lynette Sandoval]

This is the IXIT that I have for an NRFR5182. 

[Andreas]

Hi,

 

For nRF51822 +4 MHz is correct. I used the wrong document for verification, I apologize for the confusion.

 

Best regards,

Andreas