1 month ago
ble_range_dte changing tx_power
Posted bydavid_ratayczak80 points 6 repliesHello,
i am currently working with the Wireless Ranging SDK (WiRa_10.440.8.6) and trying to change the transmission power of the Dialogs (DA14695). In ble_range_dte_task.c in line 97 the tx_power is set to GAP_TX_POWER_MAX by default (which is 6dBm according to the enum in ble_gap.h, line 239-260), but if i change the power to, e.g the minimum (GAP_TX_POWER_MIN) the rssi values don't change, only the agc. Even if i disable the agc auto freeze so that the agc level is fixed at 7, the rssi values remain the same.
It seems like the transmission power is not being affected by the tx_power variable and that the agc level is doing nothing.
Why is that? Shouldn't the RSSI values correlate with the transmission power? How can i successfully change the transmission power?
1 month ago
I tried setting the Tx power to -18dBm, but the rssi values are still unchanged. In the pictures 6dBm and -18dBm you can see, that the agc is changed, but the rssi values aren't. So i tried fixing the agc level again, in the pictures 6dBm_fixed_agc and -18dBm_fixed_agc you can see the result. The rssi-value is still the same.
If i put something in between the initiator and responder the rssi values do change, so the boards can detect a power difference, if there is one.
| Attachment | 大小 |
|---|---|
| 6dBm | 67.87 KB |
| 6dBm_fixed_agc | 66.21 KB |
| -18dBm | 64.95 KB |
| -18dBm_fixed_agc | 66.58 KB |
1 month ago
Hi David,
Thanks for the findings. Let me check this and I'll get back to you.
Thanks, PM_Dialog
1 month ago
Hi David,
Thanks for the reminder. I have escalated this internally.
Thanks, PM_Dialog
1 month ago
Hi David,
Apologies for the delay. Please see below from the Team internally :
TX Power for the DTE tone exchange sequence can be adjusted in WiRa SDK10.440.8.6 release. You will see the effect by the AGC level adjusting to the new received signal strength.
The reported RSSI value is however not for the DTE signals, but for the last BLE packet transmitted before the DTE.
In a next WiRa release the RSSI value reporting will be altered to report the DTE signal strength instead of the BLE signal strength.
Thanks, PM_Dialog
1 month ago
Hi david_ratayczak,
Thanks for your question online and pointing this out. Could you please try to set the Tx power to a different value? For example, configure the Tx power @ -18dBm by setting the dte_params.tx_power to GAP_TX_POWER_MINUS_18_dBm. Are you able to see any difference?
Thanks, PM_Dialog