SDAA251 March   2026 DS90UB948-Q1

 

  1.   1
  2.   Abstract
  3. 1Introduction
  4. 2AV MUTE Mode
    1. 2.1 AV MUTE Mode in HDCP
    2. 2.2 FPD-Link HDCP Device Family-UB and UH
  5. 3UB Device Can Incorrectly Enter AV MUTE State
  6. 4How to Prevent Entering AV MUTE Mode
    1. 4.1 Prevent Video Signals During the Blanking Interval
    2. 4.2 Fix EQ Value
    3. 4.3 How to Find EQ Value
  7. 5Summary
  8. 6References

5 Summary

In unstable link environments, it is possible for the FPDLINK deserializers to experience repeated lock drops and potentially entering a state where the EQ value is operating outside of the normal range of a given system. In this extreme environment, the EQ may boost noise in such a way that the deserializer interprets this noise as the signal to enter AV MUTE mode even on a non-HDCP enabled device. The designs proposed in this document are intended to solve the inadvertent entry into AV MUTE mode by preventing this signal from being recognized but also by helping stabilize the EQ range in this type of environment.