title: Note: Directly measuring the direct digital synthesizer frequency chirp-rate for an atom interferometer.
abstract: During gravity measurements with Raman type atom interferometry, the frequency of the laser used to drive Raman transition is scanned by chirping the frequency of a direct digital synthesizer (DDS), and the local gravity is determined by precisely measuring the chip rate α of DDS. We present an effective method that can directly evaluate the frequency chirp rate stability of our DDS. By mixing a pair of synchronous linear sweeping signals, the chirp rate fluctuation is precisely measured with a frequency counter. The measurement result shows that the relative α instability can reach 5.7 × 10(-11) in 1 s, which is neglectable in a 10(-9) g level atom interferometry gravimeter.
authors.affiliation: MOE Key Laboratory of Fundamental Physical Quantities Measurement, School of Physics, Huazhong University of Science and Technology, 1037 Luo Yu Road, Wuhan 430074, People's Republic of China.
authors.forename: Juan-Juan
authors.initials: JJ
authors.lastname: Tao
authors.affiliation: MOE Key Laboratory of Fundamental Physical Quantities Measurement, School of Physics, Huazhong University of Science and Technology, 1037 Luo Yu Road, Wuhan 430074, People's Republic of China.
authors.forename: Min-Kang
authors.initials: MK
authors.lastname: Zhou
authors.affiliation: MOE Key Laboratory of Fundamental Physical Quantities Measurement, School of Physics, Huazhong University of Science and Technology, 1037 Luo Yu Road, Wuhan 430074, People's Republic of China.
authors.forename: Qiao-Zhen
authors.initials: QZ
authors.lastname: Zhang
authors.affiliation: MOE Key Laboratory of Fundamental Physical Quantities Measurement, School of Physics, Huazhong University of Science and Technology, 1037 Luo Yu Road, Wuhan 430074, People's Republic of China.
authors.forename: Jia-Feng
authors.initials: JF
authors.lastname: Cui
authors.affiliation: MOE Key Laboratory of Fundamental Physical Quantities Measurement, School of Physics, Huazhong University of Science and Technology, 1037 Luo Yu Road, Wuhan 430074, People's Republic of China.
authors.forename: Xiao-Chun
authors.initials: XC
authors.lastname: Duan
authors.affiliation: MOE Key Laboratory of Fundamental Physical Quantities Measurement, School of Physics, Huazhong University of Science and Technology, 1037 Luo Yu Road, Wuhan 430074, People's Republic of China.
authors.forename: Cheng-Gang
authors.initials: CG
authors.lastname: Shao
authors.affiliation: MOE Key Laboratory of Fundamental Physical Quantities Measurement, School of Physics, Huazhong University of Science and Technology, 1037 Luo Yu Road, Wuhan 430074, People's Republic of China.
authors.forename: Zhong-Kun
authors.initials: ZK
authors.lastname: Hu