Does the AVR pass along the data or re-transmit the stream? A repeaters function is to re-transmit the data. If there is no OSD or video processing than the data is simply re-transmitted and I assume re-clocked.
If there is OSD or video processing than and it is entirely new data that is sent because each frame/field is not the same as the original from the source.
Why does an AVR cause problems when there is none when going direct from the source to display?
A number of reasons can exist for this. But, let's keep the first part of this simple. The AVR isn't as tolerant of an out of spec signal. For example a cable box is putting out 3.5 volts. The TV accepts anything with 3.3 volts or higher. The AVR goes by the spec and only accepts signals by HDMI minimum spec of 4.7 volts. When you add the AVR you have no picture, is it the AVRs fault? Of course not! But, since we have no inexpensive way of testing this stuff our logic tells us it is.
Another problem is electronics. A "1" in binary is nothing more than positive voltage. So to make a "1" we turn on the voltage. I'll use 5 volts and seconds for example.
We turn on 5 volts and we keep it on 1 second, and then turn it off. This creates a square wave. Our receiving device needs see at least 4.7 volts for .95 seconds before it receives the "1" otherwise we get no picture.
If we have too much resistance in the circuit that voltage will be reduced and the receiver won't be see the wave and we will get no picture.
If we have too much capacitance in the circuit it takes longer for the voltage to go from 0 to 5 volts. This is called the rise time. So now the first line of our "square" wave is curved instead of going straight up. On an oscilloscope this looks like what I call a shark fin. Now at 4.7 volts the wave is not long enough to see if for .95 seconds and we get no picture. Now remember this is all being done in billionths of a second and not .95 seconds.
These problems can happen anywhere in the chain of equipment and there can be cumulative problems within a circuit if not well designed. So it doesn't matter if the receiver is re-transmitting the data if there is a problem with the circuit.
There are of course other problems that can happen. EMI/ RF interference, crosstalk, timing errors such as inter-pair skew because so far we have only talked about 1 channel of data, etc.
Hope this helps or maybe Jeff can give a better description. I'm done for tonight.
