CC2564MODN: Unexpected RSSI measurement

Francois Charlot

Part Number: CC2564MODN
Other Parts Discussed in Thread: CC2564

Hello,

My customer evaluates CC2564MODNEM. He measures an RSSI of -59 to -60 dBm at 1 meter when he would expect -40 dBm. TX level is 0 dBm. Here is his setup:

- Xubuntu 17.10 VM running the Bluez5 stack.

- RSSI measurement with a non-TI BLE module (see notes) configured with 0 dBm TX power

- Console attached to CC2564 with command hciattach -t 250 ttyS0 texas 115200

- Then use the bluetoothctl software, command scan on

- Read the RSSI data corresponding to the external BLE module with bluetoothctl

Please advise if anything should be changed in this setup. THank you.

Best regards,
François.

over 6 years ago

0 S over 6 years ago

TI__Mastermind 35795 points

Francois
Is the test done in RF shield room ? Did customer run conducted measuments too ?

Saurabh

0 KERBRAT JEAN-MARIE over 6 years ago in reply to S

Prodigy 30 points

Hi Saurabh,

The test was conducted simply "on the desk". I tried also to put the BT LE transmitter module @ 2/3mm from the TI module; The RSSI then drops to -19/-20dBm, so the 20dBm delta is still present; the Tx module is set at 0dBm level for advertisements requests. I could understand maybe -3/-5dBm for measurements errors, but not -19/-20 dBm...

0 S over 5 years ago in reply to KERBRAT JEAN-MARIE

TI__Mastermind 35795 points

Hi,
Are you able to run PER/BER tests on device ?
processors.wiki.ti.com/.../CC256x_Testing_Guide

Thanks
Saurabh

0 Francois Charlot over 5 years ago in reply to S

TI__Mastermind 25027 points

Hi Saurabh,

Such measurements require an expensive piece of equipment the customer did not intend to rent at this stage of the project. He hopes we could suggest why we see such a large discrepancy in the RSSI level when the antennas are just placed a few millimeters away. Any idea?

Best regards,
François.

0 Rizwan Murji over 5 years ago in reply to Francois Charlot

TI__Genius 12270 points

Hi Francois,

You really need to have this in a controlled environment. Usually the test against the Datasheet is done with a signal generator with the proper noise floor transmitting the signal and the DUT receiving it. I understand you don't have this.

One suggestion to try to make it a more controlled environment would be do a conducted test from one device to the other. This will be more controlled where you know the power from one device to the other and see if there is an improvement.

I hope this helps.

Thanks,
Riz

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CC2564MODN: Unexpected RSSI measurement