David Brinkley

After ''a lifetime'' at NBC, David Brinkley is preparing himself for his debut on ABC. On Sunday Brinkley hosts the premiere of an innovative news interview show, incorporating hard news, in-depth reporting, and comment, titled ''This Week'' (ABC, 11:30 a.m.-12:30 p.m.). I chatted with him long distance in Washington, where he makes his home.

''It is unique in that we will prepare the viewer with background information before the guest interviewee appears to be questioned by ABC newsmen, often including Barbara Walters, and then we will have a sort of round table which may include Ben Bradlee, George Will, and Karen Elliott House. Finally, I will do a little commentary and that will be it.''

What would he like the program to accomplish?

''When it is over, I would like for the audience to feel it has a real understanding of at least one public issue. Viewers will have been told who the guest is, what the issue is, etc. Then, with that background they will be able to listen to the questioning and be able to see whether or not the guest is responsive or evasive. I hope when we are through, viewers will have gotten some new ideas and will understand a little bit more than before we came on the air.''

Who will be the first guest? At press time, it was expected that Jimmy Carter would kick off the show.