188.8.131.52. General PMA Tuning Guidelines
- Minimize your use of TX equalization.
Table 46. Recommended TX Attenuation Value (VOD) Insertion Loss < 10 dB > 10 dB TX equalization Attenuation Value (VOD)
This is only useful for loopback tests; it does not apply for actual applications. For actual applications, tune the launch VOD of the link partner to get the optimal BER at the E-tile receiver.
- Sweep the GS1 and GS2 parameters when possible.
Table 47. Typical GS1/GS2 SettingsFor lower data rates with higher insertion loss, you can use higher values. Insertion Loss < 13 dB > 13 dB GS1 0 1 GS2 1 2
- The typical values for RF_B0 and RF_B1 are 1 and 4. For high data rates (50 Gbps and above) and for longer channels (20 dB and above), you can use a RF_B1 value of 6 or 8 (maximum) to take advantage of full EQ capabilities. Depending on the system and temperature ramp, you may be required to use a RF_B0 setting of 2 to allow sufficient room on both up and down ramps.
- Sweep the RF_B0/RF_B1 values and apply optimized values for a channel or group (short/medium/long) of channels whenever possible.
- During continuous adaptation, fixing LF_Max (which limits the LF adaptation range) and adapting RF_B0 provides the best performance over temperature ramp.
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