Gain decrease in tdd mode

HI Alirad 

Please find below.

1. AGC Configuration Asymmetry

Even though both channels are configured similarly, there might be subtle differences in:

• AGC thresholds
• Gain table settings
• AGC mode (e.g., peak vs hybrid)
• Min/max gain index limits

Check the AGC configuration for Channel 2 in TES or via API to ensure:

• minGainIndex = 183
• maxGainIndex = 255
• resetOnRxonGainIndex = 255 (if applicable)

2. TES Profile or Initialization Bug

There may be a bug or misconfiguration in the TES-generated profile for Channel 2. This has been observed in other contexts (e.g., frequency hopping mode) where gain settings freeze or behave unexpectedly.

3. Channel-Specific Calibration or Front-End Differences

If the front-end path for Channel 2 has different gain characteristics (e.g., due to layout, component tolerances, or calibration), the AGC might respond differently.

4. AGC Settling Time or Attack Delay

If the AGC doesn’t have enough time to settle after RX enable, it might prematurely reduce gain. Try increasing:

• attackDelay_us
• gainUpdateCounter

Recommendations

1. Compare AGC Configurations for Channel 1 and Channel 2 in TES or via API.
2. Force AGC Reset on RX enable for Channel 2: 
   adi_adrv9001_RxGainControl_ResetOnRxonGainIndexSet(device, channel2, 255);
3. Check Gain Table Entries for Channel 2 — ensure they match Channel 1.
4. Try Manual Gain Mode temporarily to isolate AGC behavior.
5. Update TES and Firmware to the latest version — some AGC bugs have been fixed in recent releases.

Regards,

SJ