In this paper, we review a new piece of equipment that allows one to characterize the phase noise of crystal resonators using a phase bridge system with carrier suppression. This equipment allows one to measure the inherent phase stability of quartz crystal resonators in a passive circuit without the noise usually associated with an active oscillator. We achieved a system noise floor of approximately -150 dBc/Hz at 1 Hz and -160 dBc/Hz, at 10 Hz. A SPICE characterization of the carrier suppression system is given. An investigation of the phase modulation (PM) noise in 10 MHz BVA, SC-cut quartz crystal resonator pairs is presented.

Untethered small-scale robots can be potentially used in medical applications such as minimally invasive surgeries and targeted drug delivery. This paper introduces a new localization method using Electrical Impedance Tomography (EIT), which is an emerging medical imaging technique, to dynamically track small-scale robots. The proposed approach provides the electrical conductivity distribution within the robot workspace from a set of electrical stimulations and voltage measurements gathered from eight electrodes placed at its boundary. The position of the robot can be deduced from the conductivity map that is reconstructed with the contrast in electrical properties between the robot and the background medium. This method is experimentally validated by successfully tracking the 2D motion of 4 different magnetically actuated robots within a cylindrical arena (30 mm in diameter and 4.2 mm high). The smallest detected robot is 1.5 × 1.5 × 1 mm 3 . The proposed tracking method provides a non-invasive technology with low-cost and high-speed potential that would be significant and useful for the position feedback control of untethered devices for biomedical applications in the future.

New hyperstable quartz oscillators are presented. Methods to overcome limitations due to various noise sources are discussed. Stabilities down to 5.are obtained together with drift down to 5. IO-1 2/day and excellent resistance to bad environmental conditions.

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