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ADV7180 inputs

Question asked by HankZ on Oct 1, 2013
Latest reply on Oct 1, 2013 by GuenterL

Can the ADV7180 support ITU-R BT.601. I know the ADV7180 encoder the input analog signal into a ITU-R BT.656 output. Not sure if when the device supports ITU-R BT.656 it will inherently support ITU-R BT.601 since it’s just a black and white picture.

 

We will be passing NTSC, PAL, and CCIR  Black/White 1.4V video. Will the ADV7180 support 1.4V CCIR BW video?  If the 1V peak to peak sampling of the ADV7180 is an issue, would a simple voltage divider to bring that 1.4V to a voltage less than 1V pp work?

 

If we’re dealing with BW analog video would the CrCb element of the signal be all 0s? If so than if we use the 16-bit mode of the ADV7180, bits 0-7 would be all 0s in the 16-bit mode, correct? (data sheet table 100). The reason for this questions is because we noticed that if we use the 16-bit mode on the output from the ADV7180 the digital datarate will be large compared to what we have allocated. We allocated 156Mbps per channel for the digitized video. If we use the 16-bit mode we get 16*27MHz LLC clock = 432Mbps! However, since the customer has stated that they’ll be passing BW video through this device, I believe CrCb = 0, so even if we use bits 8-16, with 0-7 all 0s, this should give knock down the datarate to 8*27 = 216Mbps, which we can work with. We’ll have to increase our initial allocation, however not drastically. Just want to make sure in the case of BW video, inferring that CrCb = 0, the 8 LSB can be ignored without any issues. We need to confirm this to be absolutely certain this is safe and will work.

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