Changes between Version 3 and Version 4 of WARPLab/AGC

Timestamp:

Nov 9, 2015, 11:17:41 AM (8 years ago)

Author:

chunter

Comment:

--

WARPLab/AGC

@@ -11 +11 @@
 1. When triggered, the AGC first selects an LNA gain based upon the RSSI signal provided by the transceiver. It does this by first converting the digital RSSI measurement into an receive power estimate in dBm. With this value, the AGC chooses one of the three possible LNA gain settings that minimizes EVM. The [https://datasheets.maximintegrated.com/en/ds/MAX2828-MAX2829.pdf MAX2829 datasheet] provides graphs that show EVM for each LNA gain setting as a function of receive power.
 2. The act of changing the LNA gain affects the RSSI measurement. After RSSI has a chance to settle from the previous LNA gain adjustment, the value is re-read and is used to make an initial, coarse, update to the baseband gain stage.
-3. After the both the LNA gain and the baseband gain have been adjusted based on RSSI, a final refinement to the baseband gain is made by the AGC based upon waveform's I and Q values themselves. Prior to this stage, the waveform cannot be trusted for an accurate power measurement since it is likely saturating the radio's ADCs. Using the waveform's I and Q values to refine the baseband gain introduces an important [#waveformDependence waveform dependence] -- during the window that the AGC inspects the I/Q waveform, the magnitude of the signal must be periodic in 16 40-MHz samples. 
+3. After the both the LNA gain and the baseband gain have been adjusted based on RSSI, a final refinement to the baseband gain is made by the AGC based upon waveform's I and Q values themselves. Prior to this stage, the waveform cannot be trusted for an accurate power measurement since it is likely saturating the radio's ADCs. Using the waveform's I and Q values to refine the baseband gain introduces an important [#waveformDependence waveform dependence] -- during the window that the AGC inspects the I/Q waveform, the magnitude of the signal must be periodic in 16 40-MHz samples. A series of 20 MHz-wide 802.11 STS symbols meets these requirements.
 
 == DC Offset Correction based on Received I/Q ==
 
+After the final gain adjustments are made, the AGC core can optionally subtract any detected DC offset. This also produces an [#waveformDependence waveform dependence -- the transmitted I and Q waveforms must be zero mean over a period of 32 samples. A series of 20 MHz-wide 802.11 STS symbols meets these requirements.
+
 == Dependence on 802.11's STS == #waveformDependence
+
+
+== AGC Characterization ==