AWR2243: SPRACV2 Application Note - Cascade Coherency and Phase Shifter Calibration Application Note - Questions about data

Hi Jacob,

              Factory calibration would be needed for each sensor. 

The separation of the values is based on the VCO1 and 2.

Regards

Hi Abhed,

So to clarify, the lookup table in A-4 would be an example from one device and should be only used as reference?

Or do you calibrate each sensor at the factory and choose the appropriate calibration from the table?

And for the separation of the values, they don't line up. The table has the bands mentioned in my email and those don't match the different VCO ranges. Can you clarify that a bit?

Hi Abhed,

Any clarification here?

Hi Abhed,

Please advise.

Hi Jacob,

                 Apologies for the delay.

The table A-4 is a Fixed LUT for AWR2243 and it shows the impact of the temperature on phase shift. This is classified based on VCO frequency band of frequency. 

The VCO1 is 76 to 77GHz and VCO2 is 76 to 81GHz. For coherency app note, have taken the input to get it fixed.

regards

Hi Abhed,

Thank you for the confirmation that there is currently a typo in the application note. We will monitor for that to be updated.

This leads to a second question. During calibration, we do not have the option/choice on which VCO band to use for calibration. However, the phase calibration table depends on the VCO band. Why does the phase shift calibration depend on VCO band when we can't control the VCO band for initialization?

Hi Abhed,

Following up here. Any guidance on the above?

Abhed please advise.

Hi Jacob,

                 The AWR_PROFILE_CONF_SB does allow you to force the VCO.

Regards 

Thanks for the clarification Abhed.

When triggering the phase shifter calibration during the rfinit phase, do we need to send before the profile configuration to force the usage of VCO1 or 2?

Because today, it does not seem possible to select which VCO is used during the phase shifter calibration step although it looks like a key parameter for PS calib.

Hi,

         I think we are talking about 2 different things here.

Few points:

1. Please do not link the Phase shifter calibration with VCO. The typo which i was referring to was to VCO's band range not consistent across documents.

2. The Phase shifter calibration are done for each TX. 

3. The Frequency band given in the app note is for indicative usage based on the frequency band of use in your profile. There could have been one LUT covering the entire 76 to 81GHz also, but the sole purpose of giving 2 LUT's for 76-77 and 77-81 is to have more tuned performance of phase shifter frequency vs temperature wise.

4. Based on your profile's cal mon frequency limits pick up the LUT which is suitable for you.

Regards

Hi Abhed,

Your point number one is very confusing because if phase shifter calibration value is NOT linked to VCO1 or 2, I would expect that the PS calibration value is identical whatever which VCO is selected. However it doesn't seem to be the case:

1 - So I need to ask again, why is there a different phase shifter calibration value between 2 VCO band if these value are expected to be independent of the VCO in use?

2 - This TX Phase Shifter Calibration correction value should be added on top of the TX phase shifter calibration value stored at factory level under measured under controlled environment.. Measurement is done during the RfInit phase. Could you also confirm that no profile needs to be configured (to select VCO for example) before triggering the RfInit phase?

Regards,

Hi,

1. There are different phase shifter calibration values as they are centered at different frequency bands at which there LUT's are covering. For example: 76-77GHz LUT is focused at 76 to 77GHz of band of operation with 76.5GHz center freq. The 77-81GHz LUT is focused at 79GHz center frequency. If your profile is going to use the 76.125 to 76.6GHz then you should use the first LUT as that would be more tuned to the band of operation. however, if your profile operates from 76.125 to 78GHz then second LUT is what you should use as that will covering your entire profile.

2. Phase shifter cal is taken care by the firmware at RFinit, hence would not be requiring any configuration or control from user for the same. Also you don't have to configure or select any VCO for the same.

Regards