Testing DS34RT5110

Hi Jeffrey,

I think, based on your test, this means your HDMI cables do not present much loss or attenuation. Please attached find different test/cable reach test we did using DS34RT5110 device. 

Also you can use VOD control pins to change the eye height(if this is what you need to do). 

Regards,,nasser6283.HDMI Demo Kit for HDMI Cables.pdf

Hi Jeffrey,

For some reason i am trying to send you one more app note but the size limit does not allow me to do so. Please send me email directly and i can email this to you.

Regards,,nasser

Nasser:

Thank you so much for your help.

I have run the eval on several longer cables. On the shorter ones the system worked fine. However when I reduced the EQ I  lost the signal as expected. However, when I looked at the waveform the Eye was well above the mask base. Rotating the EQ control, not the pre-empt control, it made little difference. I would have expected the eye to calapsed into the mask and it didn't. One of our engineers told me it was because of the reclocking feature so the testing with our test equipment would have to be done differently, at least that's what he though. I will have another chance to  do this next week. I could send you the eye patterns if that would help.

Thank you

Jeff

Hi Jeff,

I tend to agree with your colleague. The reclocker slices and retimes the signal thus no matter what cable length you use you would see a good eye but you could be getting bit errors. You can try to put the device in Bypass mode this way the retimer is disabled. You may see eye degradation as you increase the cable length.

Regards,,nasser

Thank You Nasser

I will try that next week. I don't quite understand what you mean. I would have thought the reclock would recover the clock and not the TMDS lines. The TMDS lines have the same symptom. How does the slicing occur? Is there an app or white paper on this?

Also, I have had a lot of difficulty returning your mail. It does not seem to like going back to reply. I have to try many times before it works.

Just an FYI

Jeff

Nassner:

We have completed the build with the DS34RT5110. The unit works fine except an intermittent audio output.

No real pattern, just random cut out. There is now effect with the video. The video is perfect.

I now the audio is put up on one of the TMDS lanes so I not sure why the audio would cut out. I tried this with all eq settings and multiple lengths.

Thank you again

Hi Jeffrey,

Could you please send us a block diagram of your system or the HDMI receiver? It is odd that video is fine but you are getting audio cut outs.

Regards,,nasser

Nasser:

Attached is the schematic we used. I have done more work on this since I wrote and find this happens pretty much all the time on any length of cable. I also used HDMI cable that had better performance but still the audio will drop out leaving the picture perfectly in tact.

I have increase the filtering on the power supply also, although the amount of noise on that bus is less than 5mil pp.

Thank you for your help on this.

Jeff

Hi Jeff,

Thanks for sending us the schematic.

Could you please send us a block diagram of your overall test setup? For example what instrument is generating the video and audio. Also, what instrument is decoding the vido and audio. It will help us to understand the overall test setup you are using.

Regards,,nasser

OH,  in final test it is just a BluRay player and an HDMI Display.

Block attached.