A new strategy has been developed to measure cross-correlation rates with much enhanced accuracy. The method relies on the use of four complementary expts. Errors due to pulse miscalibration and to uncontrolled attenuation factors assocd. with relaxation are cancelled out. Problems due to violations of the secular approxn. are greatly alleviated. The method has been applied to the measurement of N/NH (CSA/DD) cross-correlated relaxation rates in human ubiquitin. [on SciFinder (R)]