There will be no lying at the National Cable Television Assn. convention in Atlanta. At least, not at the Court TV booth.Show attendees at the booth on May 4 and 5 will have an opportunity to be hooked up to a polygraph machine for a five-minute lie detection session administered by veteran examiner Gene Cella. If that doesn’t sound like a blast all by itself, consider that test-takers will have a pneumatic tube attached to their chest and stomach to measure respiratory changes, metal clips affixed to two fingers to discern changes in moisture and a cardio cuff strapped to an upper arm to gauge blood pressure and heart rate. As if working in the cable industry doesn’t induce enough paranoia.