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Summary: The energy coupling behavior is propagated through the magnetic field and would seriously affect the operation performance of two‐degree‐of‐freedom motion system based on linear‐rotary motor. This paper proposes a novel double‐stator linear‐rotary switched reluctance motor (DSLR‐SRM) to suppress the energy coupling behavior. First, the structure and operation principles of DSLR‐SRM are presented. The two stators of DSLR‐SRM are radially arranged to perform the independent magnetic circuit and suppress the energy coupling behavior through the magnetic field. Then, an equivalent circuit model is established to shorten the modeling and calculation time. It could be found that the energy coupling behavior directly affects the torque and force performance. Next, the sensitivity of the DSLR‐SRM dimensions is developed. Meanwhile, the dimensions of DSLR‐SRM are optimized to enhance the torque and force output via TOPSIS decision‐making. Finally, the validity of equivalent circuit modeling analysis and optimization results are verified through three‐dimensional finite element model. [ABSTRACT FROM AUTHOR]

The natural frequency of traditional velocity sensors such as moving coil geophones limits their measurable low-frequency range, and the damping ratio affects the flatness of the sensor in the amplitude and frequency curves, resulting in variations in sensitivity over the available frequency range. In this paper, the structure and working principle of the geophone are analyzed and its dynamics are modeled. After synthesizing the negative resistance method and zero-pole compensation, two commonly adopted low-frequency extension methods, a method for improving low-frequency response, which is a series filter and a subtraction circuit to increase the damping ratio, is proposed. Applying this method to improve the low-frequency response of the JF-20DX geophone, which has a natural frequency of 10 Hz, results in a flat response to acceleration in the frequency range from 1 to 100 Hz. Both the PSpice simulation and actual measurement show a much lower noise level via the new method. Testing the vibration at 10 Hz, the new method has a 17.52 dB higher signal-to-noise ratio than the traditional zero-pole method. Both theoretical analysis and actual measurement results show that this method has a simple circuit structure, introduces less circuit noise, and has a low-frequency response improvement effect, which provides an approach for the low-frequency extension of moving coil geophones. [ABSTRACT FROM AUTHOR]

By using a mixer to down-convert the high frequency components of a signal, digital bandwidth interleaving (DBI) technology can simultaneously increase the sampling rate and bandwidth of the sampling system, compared to the time-interleaved and hybrid filter bank. However, the software and hardware of the classical architecture are too complicated, which also leads to poor performance. In particular, the pilot tone used to synchronize the analog and digital local oscillators (LO) of mixers intermodulates with the high frequency components of the signal, resulting in larger spurs. This paper proposes a synchronous mixing architecture for the DBI system, where the LO of the analog mixer is synchronized with the sampling clock of the analog-to-digital converter. Its hardware and software are simplified—the pilot tone used to synchronize the LOs can also be removed. An evaluation platform with a sampling rate of 250 MSPS is implemented to illustrate the performance of the new architecture. The result shows that the spurious free dynamic range (SFDR) of the new architecture is more than 20 dB higher than the classical one in a high frequency range. The rise time of a step signal of the new architecture is 0.578 ± 0.070 ns faster than the classical one with the same bandwidth (90 MHz). [ABSTRACT FROM AUTHOR]