Hello,
I found that the EQ gain control register allows us to set the EQ stage 1 bypass to disable or enable bypass.
Best Regards,
Hitoshi
Hi Hitoshi-san,
A clarification I would like to make is that the "eq_stage1_bypass" field controls a specific CTLE amplifier that is called "EQ Boost 1 (2nd order)" in our DS320PR810 GUI.
This amplifier is also controlled by the "eq_profile_3:0" field when the bypass is not enabled, and it is different from the generic "EQ Boost 1" amplifier.
Does this mean I can bypass the equalizer and get the equivalent of 0 dB gain and no equalizer?
When the "eq_stage1_bypass" field is enabled, the "EQ Boost 1 (2nd order)" amplifier is bypassed. However, the two other amplifiers you can see in the image ("EQ Boost 1" and "EQ Boost 2") are always in the signal path and do not have bypass modes. Even when these amplifiers are both set to a setting of 0, they will still provide a small amount of total EQ boost of approximately 4 dB @ 16 GHz. You can see that this is the combination associated with EQ index 0 in Table 7-1 of the datasheet, representing the minimum amount of equalization that the device can provide. So there is no true device level bypass.
What does "1 bypass" mean?
When the "eq_stage1_bypass" field is set to 1, the "EQ Boost 1 (2nd order)" amplifier is bypassed. When this field is set to 0, the amplifier is active and the strength is controlled by the "eq_profile_3:0" field.
For most customers it is sufficient to control the device equalization through the EQ Index system, which are premade combinations of amplifier settings that form a gradual step of minimum to maximum total equalization. Studying and changing the individual amplifier settings is complicated and usually not necessary, especially during early testing.
Let us know if you have other questions.
Best,
Evan Su
