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AD9380, Macrovision signal levels

Question asked by cjameshuff on Jun 24, 2011
Latest reply on Jul 27, 2011 by cjameshuff

We are using the AD9380 with a 576i YCbCr component video source (with embedded sync-on-green) with Macrovision. We are getting tearing at the top of the image and field errors when the Macrovision pulses go through a sequence where they rise gradually to a high-brightness value. We have an input network essentially identical to that on the AD9880 eval board, with input ferrite beads, 75 ohm resistors to ground, and 47 nF capacitors to the RGB inputs and a 1 nF capacitor to the SOG input.

 

The signal that causes the problem has an amplitude of about 1.2 V peak-to-peak due to the high intensity Macrovision pulses. According to the datasheet, the inputs are only rated for an input range from 0.5 Vpp to 1.0 Vpp. Putting a 220 ohm resistor from the video input to ground pulled the signal down to just slightly over 1.0 Vpp, and eliminated the video disturbances.

 

However, this certainly does not seem like the right way to fix the problem. Has anything like this issue been encountered before? How does the AD9380 handle excessive input levels, and what might be done to improve things?

 

To make sure the issue isn't something else that happens to be triggered by the Macrovision signal, can I get the suggested clamping, gain/offset, and other settings for this video format?

 

edited to add: I've also reproduced the issue with 480i video. The signal source is a Pioneer BDP-33FD Blu-ray player playing various standard DVDs.

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