VELOCITY DISTRIBUTIONS CALCULATED FROM THE FOURIER-TRANSFORMS OF RAMSEY LINESHAPES

A computerized method for finding velocity distributions from the Four ier transforms of Ramsey Iineshapes has been developed, Experimental a nd numerical tests of the method show that it works very wed for broad distributions and lineshapes where the drift time is much longer than the excitation time, The method is routinely used to find velocity di stributions for the primary frequency standard NIST-7, The second-orde r Doppler shift is calculated from these distributions,vith an uncerta inty of a few tenths of 1 percent.