search

open-sdr / openwifi-hw

open-source IEEE 802.11 WiFi baseband FPGA (chip) design: FPGA, hardware
GNU Affero General Public License v3.0
701 stars 237 forks source link

iq rssi db signed value #111

Open rookiebeotch opened 3 months ago

rookiebeotch commented 3 months ago

in rssi.v the iq_rssi_half_db is defined as signed 9 bit value.

In vivado ILA i see this value as non negative but it decreases as rf signal goes higher. it acts like a negative number but MSB isn't 1

wanted to confirm that this calculation is supposed to be negative for low signals like -80dBm.

JiaoXianjun commented 2 months ago

If I remember correctly, iq rssi means sth proportional to the iq amplitude. But please remember that between rf signal and the iq sample, there is gc (gain control) in between playing. So I suggest turning off AGC? https://github.com/open-sdr/openwifi/blob/master/doc/app_notes/frequent_trick.md#Rx-gain-config