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Frequency Synthesis Technique for 60 GHz Multi-Gbps Wireless
Published in Christopher Siu, Krzysztof Iniewski, IoT and Low-Power Wireless, 2018
Teerachot Siriburanon, Hanli Liu, Kenichi Okada, Akira Matsuzawa, Wei Deng, Satoshi Kondo, Makihiko Katsuragi, Kento Kimura
where AVCO is an amplitude of VCO, τRC is an RC time constant of wave shaper, TDIV is the period of output of ILFD, ICP1 is charge-pump current in SSPD, Vgs,eff is effective gate bias of n-channel MOSFET (NMOS) transistor, TREF is a period of reference clock, τpul and is a controlled pulse width. The in-band phase noise of SSPD can be computed by Lin-band,SSPD = Si,CP1/2α2SSPD. Since a division ratio is reduced from 1200 to 4 in the subsampling feedback path, this helps to alleviate SSPD noise that can be brought below noise of reference clocks. In this work, loop bandwidth is set to approximately 400 kHz to optimize both RMS jitter and out-of-band phase noise performance. To further lower power consumption, a divide-by-4 dual-step-mixing ILFD is used in the 20 GHz SS-PLL, and a 60 GHz gm-enhanced QILO is implemented for subharmonic injection locking. In the next section, the design of key building blocks will be discussed in detail.
MONOLITh: a soft non-pneumatic foam robot with a functional mesh skin for use in delicate environments
Published in Advanced Robotics, 2022
Anthony E. Scibelli, Cassandra M. Donatelli, Ben K. Tidswell, Micah R. Payton, Eric D. Tytell, Barry A. Trimmer
To test how the foam material performs in tension we created ‘dog bone’ shaped samples with testing cross section measuring 2.54 × 1.27 cm (n = 18, 3 at each velocity). Samples were held in tensile grips on the Instron testing frame and linearly deformed at 2, 7, 10, 12, 15, and 20 cm/min. These velocities were selected to match the expected minimum and maximum locomotion speeds provided by the motors. A set of samples underwent cyclic tension testing as well cycling five cycles at the same respective range of velocities. While we have not performed long-term fatigue testing, the prototypes we used functioned well for dozens of hours. The only perceivable difference over that time has been a slight slowing of the recovery from deformation which increased the cycle duration. This change in material properties is common in polyurethane foams and it involves a progressive softening, and a closure of the hysteresis work loop [28]. These properties can be modified for particular applications using different urethane formulations and by manufacturing processes that alter the cellular structure of the foam [29].