Changes between Version 4 and Version 5 of SISOAGC
- Timestamp:
- Mar 14, 2007, 6:14:45 PM (17 years ago)
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SISOAGC
v4 v5 11 11 The radios apply gain at two points during downconversion: course gain is applied at RF (0, 15, or 31 dB), and a fine-grained gain is applied at baseband (0-62 dB, in steps of 2 dB). Using an analog received signal strength indicator (RSSI), the algorithm selects the appropriate RF gain. It then uses the digital signal to set the baseband gain. The choice of RF and baseband gains is determined by the target received signal setting, which is passed into the algorithm upon initialization. 12 12 13 Before the AGC runs, the gain values in the radio are calibrated such that background noise appears to the receiver at -19 dB . When a packet is detected, the AGC is triggered, chooses gains, and sets the signal strength to the target value. These gains are '''locked''' until the AGC is reset. Ideally, this reset should occur when a packet has been completely processed, so that the AGC is ready for the next packet.13 Before the AGC runs, the gain values in the radio are calibrated such that background noise appears to the receiver at -19 dBm. When a packet is detected, the AGC is triggered, chooses gains, and sets the signal strength to the target value. These gains are '''locked''' until the AGC is reset. Ideally, this reset should occur when a packet has been completely processed, so that the AGC is ready for the next packet. 14 14 15 15 == DC Offset Correction == … … 31 31 '''{{{void ofdm_AGC_Initialize(int noise_estimate)}}}''' 32 32 33 Resets and initializes the AGC peripheral with all required parameters. The initial baseband gain is computed from the noise estimate, so an accurate guess of the noise floor is required. This value is generally near -85 dB .33 Resets and initializes the AGC peripheral with all required parameters. The initial baseband gain is computed from the noise estimate, so an accurate guess of the noise floor is required. This value is generally near -85 dBm. 34 34 35 35 Upon completing this routine, the AGC is enabled and ready to be triggered by the packet detector. … … 51 51 '''{{{ofdm_AGC_SetTarget(signed int c)}}}''' 52 52 53 Sets the target signal strength value to c dB . After the AGC completes its execution, the receiver will see a signal of this magnitude.53 Sets the target signal strength value to c dBm. After the AGC completes its execution, the receiver will see a signal of this magnitude. 54 54 55 55 '''{{{void ofdm_AGC_setNoiseEstimate(int noise_estimate)}}}''' … … 81 81 xil_printf("AGC initialization...\r\n"); 82 82 83 // Call the overall init routine -- Master Reset is included in this, use -85 dB as noise floor estimate83 // Call the overall init routine -- Master Reset is included in this, use -85 dBm as noise floor estimate 84 84 ofdm_AGC_Initialize(-85); 85 85 … … 90 90 ofdm_AGC_SetDCO(1); 91 91 92 // Set the target signal strength to -15 dB 92 // Set the target signal strength to -15 dBm 93 93 ofdm_AGC_SetTarget(-15); 94 94