AnsweredAssumed Answered

Line-Blanking interval of AD7390's output

Question asked by chiguoqan on Aug 18, 2016
Latest reply on Aug 11, 2017 by Anthony_Purcell

According to the table 1-1 in ITU-R BT.470-6,  the line-blanking interval of PAL B/D/H/I/K/L should be 12us:

    https://ezchina.analog.com/servlet/JiveServlet/showImage/2-36044-10970/aa.jpg

https://ezchina.analog.com/servlet/JiveServlet/showImage/2-36044-10971/a.jpg

 

But when I measure  the output of ADV7390, I found that it is about 10us.  I have config ADV7390 by using the scripts in table 82.  I think this is correct for ADV7390 when the input is set to BT656, because according to figure 104 in datasheet, the line-blanking interval should be 288 clock ( frequency is 27MHz and period is 37.037ns)  , that is 288 x 37.037 = 10.6us.

But it is not conform to th BT470, and have ariased problems in some monitors ( most monitor  is OK).  How can I changed the line blanking interval to 12us?

https://ezchina.analog.com/servlet/JiveServlet/showImage/2-36044-10969/bb.jpg

Outcomes