On June 15, 2010 at 00:57, phil said...
I think where crosen is going with this is that IF the AVR takes the incoming TMDS data, decrypts it and then re encrypts it to send it to the sink, the new encrypted signal should be a good 5vpp data stream at the point it leaves the AVR, provided the incoming signal was ok and the AVR was working properly. This would indicate a restoration of a marginal signal from a cable box, say 4.8vpp back up to 5vpp.
They "should" return signal to rail.
Most do not.
Note: this has nothing to do with timing or actually quality of "eye" pattern, just the voltage swing.
If the above were true then when the cable box direct to the TV was good but bad when run thru the AVR it would indicate a problem with the AVR or the 2nd HDMI cable. The cumulative cable/connector db loss would be restored somewhat by the AVR if it is a restorer.
If, as many here have stated, the data from the cable box goes thru the AVR untouched (unrestored) it would complicate troubleshooting an HDMI problem.
Brent in post 8 said that sub 1k AVRs DO NOT rebuild signal level and indicated that more expensive units do.
This is true.
Note: "more expensive".
It is not until you break the $1000 price point that there is any margin for doing this.
This would change what happens to HDMI inside AVRs and also change the |troubleshooting of problems with HDMI based on model.
Is there a specification on an AVR that would tell how it handles HDMI?
There is (+/-), but there are specs for a lot of things related to HDMI.
Build of Materials and design time costs limit what can be done in the real world.
Personally I can tell you that you cannot build a true 10.2g cable that supports ALL four high speed data channels, 5 volts (easy to drop this one) and DDC correctly cheap.
But I see cables listed as such (claiming HDMI cert.) and sold cheap all over the place.
HDMI LLC is not set up to be a police force and we on more than one occasion have seen a certified product drop in quality without penilty from HDMI.
This is one of the reasons that we (and other mfgr's) support the DPL program (
http://www.dpllabs.com/ ).
They provide a no bullshit product verification of performance (that is spot checked in the field).
You should note that DPL tested/certified products WILL cost more than other like spec'ed products.
The difference is that DPL rated products do what they claim, also the cost the administer the DPL program is by no means cheap, the recent upgrading of test gear for 1.4A (cables & electronics) was over $500,000.
What this means is if you want product performance that you can count on look for the DPL label.
