This section presents a detailed comparison between DAFS and XAFS measurements for Cu metal, which is an ideal system to demonstrate the equivalence of DAFS and XAFS measurements. Cu is a typical XAFS standard and was one of the first systems to be studied by XAFS. It is also an important standard for testing modern XAFS calculations. Cu has a large fine structure, a convenient K-edge energy, and a simple monoatomic FCC lattice. Because of the high symmetry of the Cu lattice, no DAFS polarization corrections are required. The results for the Cu(111) and Cu(222) Bragg reflections presented in this section demonstrate that DAFS measurements contain the same local atomic structural information as XAFS measurements, and confirm in detail the DAFS theory developed in Section 2. Both of the analysis methods described in Section 4 were used with excellent results.