Related Experiment Video
Updated: Feb 25, 2026

Frequency Mixing Magnetic Detection Scanner for Imaging Magnetic Particles in Planar Samples
Published on: June 9, 2016
A novel approach to estimating the Doppler shift frequency from quadrature mixer output
1CAS Key Laboratory of Geospace Environment, Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
Abstract:
Doppler backscattering systems (DBSs) have been widely used in magnetic confinement fusion devices to measure the density fluctuations and propagation velocity of turbulence. However, the received signals of a DBS usually include both zero-order reflection and backscattering components, which results in interference in calculating the Doppler shift frequency from the backscattering components. A novel method is introduced here for estimating the Doppler shift frequency by separating the zero-order reflection and backscattering components using the cross-phase spectrum between the I-signal and Q-signal from a quadrature mixer, based on the difference in symmetrical characteristics between the zero-order reflection and backscattering signal spectra. It is proven that this method is more effective than traditional approaches, such as multiple signal classification and fast Fourier transformation, for extracting Doppler shift information.
Related Concept Videos
Doppler Effect - II
Linear Approximation in Frequency Domain
In contrast, nonlinear systems do not inherently possess these properties. However, for small deviations around an operating point, a nonlinear system can often be approximated as linear....
Doppler Effect - I
Upsampling
Frequency-Domain Interpretation of PD Control
The proportional control gain, combined with the...
Mass Analyzers: Common Types

