The Importance of Good Signal Integrity

Ninety percent of the time, HDMI-related system failures are related to poor signal integrity.

Integrity issues can arise with Blu-ray players, A/V receivers (AVRs), settop boxes, cables, baluns, switches, displays and more. You can't afford to neglect any area.

We recently received a call regarding an HDMI system failure. The setup seemed pretty basic, with just a Blu-ray player and two settop boxes. Piece of cake, right? Well, the Blu-ray player worked for about one minute, while the settop boxes did not work at all.

A 5-meter cable was coupling the output of the AVR to the display. Reconfiguring the system by connecting the Blu-ray directly to the monitor produced "sparkles" (this isn't good). By adding de-emphasis equalization (EQ) to the cable, we cured those.

When connecting the Blu-ray back to input 1 on the AVR, the player was still OK. But the cable boxes were still kaput.

We tried both cable settop boxes on input 1 and had no problem. When we tried the Blu-ray player on inputs 2 and 3, it failed on input 2, but worked on input 3. We added HDCP correction to the output of each settop box and, finally, all problems were corrected.

Every part was at fault except for perhaps the Blu-ray player and the display. We had a poor cable, settop boxes with poor EDID and HDCP data, and an AVR that had only one input with enough integrity to play nicely. Removing the cable EQ killed everything.

So be sure to maintain good signal integrity in all equipment and installation techniques, or you're in for a really bad day.