Frequency transformations for digital filters
It is shown that the reactance transformation for an analog filter corresponds to an all-pass function transformation in the case of a digital filter. It is further shown how this result could be used to obtain in a simple way the spectral transformations for digital filters derived by Constantinides.
High Order Transformations for Flexible IIR Filter Design
Extensions of popular transformations for IIR filters are given which employ high order mapping filters. Easy control of prototype transfer function features in multiband renditions is demonstrated. A wider interpretation of transformation is also suggested which permits "less-than-N-band replication" (at a cost in dimensionality , phase fidelity and attention to stability enforcement) that is believed to be of considerable benefit in practical design situations.
Thermal-mechanical fully coupled analysis of high-speed angular contact ball bearings
The thermal and mechanical properties of angular contact ball bearings are critical to their operating accuracy and service life. On the basis of the theory of dynamics and frictional heat generation, this work establishes a thermal-mechanical fully coupled model. The high-speed motion characteristics, temperature, and dynamic stiffness are analyzed, and the simulation results are compared with the theoretical calculation and experimental results. Then, the temperature and axial deformation of the bearings under different rotation speeds are analyzed, and the laws of mechanical and thermal characteristics of the bearings are obtained. Results show that an increase in the rotation speed of the inner ring causes the temperature of each component to increase, with the contact area of the balls showing the greatest increase in temperature. An increase in rotation speed also increases the axial deformation of the inner ring.