RTOS/CC1310: Frequency Offset Compensation for cc13xx

Sergey Korobov

Part Number: CC1310
Other Parts Discussed in Thread: CC430F5137,

Tool/software: TI-RTOS

Hi,

I use cc13xx. I have a need to turn off "Frequency Offset Compensation". Can I do this?

Also I need to know, "Frequency Offset Compensation" in the received packet (necessary to adjust the frequency during the production test). how can this be done?

P.S. I am use TI-RTOS 2.20.00.06

over 8 years ago

0 TER over 8 years ago

TI__Guru**** 317180 points

Why do you want to turn off the frequency offset compensation?

Could you elaborate a bit more about your use case?

0 Sergey Korobov over 8 years ago in reply to TER

Prodigy 170 points

In the production of capacitors can be used from different parties. The capacitors will have deviation. Causing the radio frequency shift. Capacity is also dependent on the external conditions. We want exactly nastrivat frequency relative to a reference in the process of production testing. This will allow us to maximize the quality of communication.

Perhaps we do not need to switch off the frequency compensation, but it is necessary to know the frequency offset value relative to the reference.

0 Sergey Korobov over 8 years ago

Prodigy 170 points

you help me?

0 TER over 8 years ago in reply to Sergey Korobov

TI__Guru**** 317180 points

Frequency offset compensation is something we use in Rx where a estimate is calculated when the sync word is received.

What you describe is a Tx test where you can measure the actual Tx frequency using a spectrum and from this calculating the offset.

0 Sergey Korobov over 8 years ago in reply to TER

Prodigy 170 points

Do I understand correctly, with two devices on a chip that not can be done?

0 Sergey Korobov over 8 years ago in reply to TER

Prodigy 170 points

Do I understand correctly, with two devices on a СС13xx that not can be done?

0 TER over 8 years ago in reply to Sergey Korobov

TI__Guru**** 317180 points

Not sure if I understand the question/ setup. Could you post a drawing or similar how your test setup looks like?

0 Sergey Korobov over 8 years ago in reply to TER

Prodigy 170 points

I'm sorry for my bad English.

You are right I'm need to do a Tx test, to measure device's Tx frequency shift, which can be caused by different capacitors used, or low oscillator accuracy and is varied from device to device.

So the question is how to measure it, and how to correct it afterwards.

0 Sergey Korobov over 8 years ago in reply to TER

Prodigy 170 points

When I was using CC430F5137 I had this setup:
A. Pre-calibrated device based on CC430F5137
B. New device which is to be calibrated

B was sending 100 packets to A, and then A used FREQEST to calculate median B's Tx shift. Then this value was stored in B's NVRAM, and loaded to FSCTRL0 on every start.

0 TER over 8 years ago in reply to Sergey Korobov

TI__Guru**** 317180 points

Thanks for the description of the setup.

For CC1310 the frequency offset estimate is not easily available. And to take into account offset you have to set you frequency accordingly. That is if you know the offset is 10k kHz you set the frequency to 868 MHz + 10 kHz.

Since you already have a setup with a calibrated CC430 you can look into using this to receive packets from CC1310 and getting a estimate. When you get the estimate you have to use this to recalculate the frequency in CC1310.

0 Sergey Korobov over 8 years ago in reply to TER

Prodigy 170 points

Well, this is very unfortunate. Thank you for the answer.

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RTOS/CC1310: Frequency Offset Compensation for cc13xx