What am trying to do is run YPbPr analog video input into the ADV7441a and then have the digital output data run into an SDI chip to produce SDI video. Doing it this way does not produce a clean "I" out of the SDI chip and I get jittery video for 1080P59. It appears the synch seperator for the ADV7441a is not doing as good a job as required. What I want to do is connect a synch seperator chip from the analog video and then genlock the pixel clock from that chip into the External Clock input (Pin 48) of the ADV7441a. What is required of the ADV7441a to do this? Does this mean I no longer need the XTAL inputs since I will only be running YPbPr analog video into the ADV7441a? Also, can the EXT_CLK (Pin48) support 1.8V input from the clock input? We did something similar using the AD9984 and had good results and want to do the same thing using the ADV7441a.