A new simple interface circuit for quartz vibrating gyroscope (QVG) driven by square-wave is presented in this paper. The interface circuit is composed of self-excited loop of driving circuit and detecting circuit. Temperature compensation, low noise and low coupling design are adopted in the circuit to achieve the targets of rapid oscillation start, high stability on all-temperature range and linearity. The interface circuit is fabricated in a 0.5 µm CMOS process and the test results show that the scale factor is 19.94 mV/°/s with an input angular ratio range of ±200°/s. The angular random walk and bias drift are 0.095°/√hr and 2.5°/hr respectively. The non-linearity can reach to 97 ppm and the zero drift and P-P value are 20°/hr and 80°/hr at the temperature from −45 °C to 85 °C. Meanwhile, the short stability at room temperature in one hour is 8.86°/hr (1-sigma) and the start time is less than 1 s. This design realizes a high standard with a simple structure.
The research describes an intelligent electrocardiogram (ECG) acquisition system with low power and low data loss features. The system is constructed with ADS129X, MSP430X, CC254X Bluetooth low energy (BLE) with low power wireless communication protocol and smart phone for the ECG display. Two architectures, namely, with and without the microprocessor (MPU) and hinted handoff mechanism algorithm, are used to verify the data transmission loss between the BLE and the smart phone. The system not only employed low-power solution but also added full handshake and hinted handoff to achieve complete synchronization and accurate transmission reliability. The MPU method definitely enhanced the ECG packet loss rate and power saving rate to 0.63% and 49.78%, respectively.
In this letter, a right-angle full Ka-band differential microstrip line (DML) to rectangular waveguide transition is proposed. A novel coupling probe configuration, which is considered to be a combination of a strip loop and a slot loop, is developed to improve the bandwidth of the transition. The 15 dB fractional bandwidth is increased from 33 to 40.6% compared with the right-angle DML-to-waveguide transition using multilayer PCB structure. To verify this transition, a back-to-back prototype is fabricated and measured. It provides an insertion loss of less than 1.2 dB and a return loss of better than 15 dB within a wide frequency range from 26.5 to 40 GHz. The measurement results show good agreements with the simulation ones.
An inductively coupled power-transfer method is proposed using a new, brushless motor excitation method called contactless excitation system (CES). Uses a loosely coupled rotating excitation transformer (LCRET) and realize the transmission of excitation power, thereby proving to be safer and simpler than traditional excitation systems. The principles and two topologies are introduced. LCRET can achieve excitation-energy transmission when the primary and secondary sides rotate at a relatively high speed. The transient characteristics of the proposed topologies are compared using a finite element analysis to establish an optimal topology and verify the safety and high-efficiency energy transmission of LCRET by conducting tests.
This paper proposes a multi-core architecture with asynchronous clocks to prevent power analysis attacks for the first time. The multi cores normally execute different tasks with default clocks, but will execute the cryptographic algorithm together with asynchronous clocks to foil the side channel attacks. The cryptographic algorithm is split into multi parts, each of which is executed simultaneously by one core. Security analysis and simulation results show that the differential power analysis (DPA) attack and correlation power analysis (CPA) attack fail on data encryption standard (DES) and advanced encryption standard (AES) with the proposed architecture.
A generalized circuit topology and synthesis method for multiband bandpass filters with controllable center frequencies and bandwidths are proposed based on a semi-hidden multi-mode coupling element. The so-called semi-hidden multi-mode coupling element is a Π-shape multi-mode J inverter constructed by a transmission line and two multi-mode capacitors at two ends, and the multi-mode capacitors are merged or hidden into nearby multi-mode resonators, modifying the equivalent LC circuits of the multi-mode resonators at the passbands. The multi-mode J inverter gets simplified and only a connecting line needs to be implemented, which simplifies high-order multi-band bandpass filter design. For validating the filter topology and synthesis method, the circuit and design example of triple-band bandpass filter are presented by using triple-stub triple-mode resonators, and a genetic algorithm is used for extracting the parameters of the triple-mode resonators. Good features including controllable bandwidths, high isolations are achieved.
A novel, frequency selective surface (FSS) inspired, fully passive, chipless data encoding circuit capable of being operated as a radio frequency identification (RFID) tag is presented. The tag is composed of finite repetitions of the unit cell realized on a grounded FR4 substrate having an overall size of 27.5 × 30 mm2. The unit cell is made up of several triangle-shaped resonators patterned in a looped fashion. Variation in the geometric structure of the tag, achieved by addition or removal of nested loops, corresponds to a specific bit sequence. Each sequence is represented in the spectral domain as a unique frequency signature of the resonators. The proposed 10-bit tag covers the spectral range from 4 to 11 GHz. The tag is compact, robust, and exhibits a stable response to impinging signals at different angles of incidence.
This paper proposes a wideband linearity improvement technique for the CS-CG cascode structure in the Low-Noise Amplifier (LNA), in which the linearity of both CS and CG stages are improved simultaneously. At relatively low frequencies, the noise and nonlinearity contributions mainly come from the CS stage and a post-distortion method is adopted to eliminate the third-order harmonic. As the frequency increases, the nonlinearity and noise contribution of the CG stage becomes more severe due to its parasitic capacitances. A transformer feedback structure is proposed to increase the gain and reduce the noise, thereby improving the linearity of the CG stage. The linearization technique is applied to an ultra-wideband (UWB) cascode LNA to evaluate effectiveness. The designed LNA achieves a S11 of less than −10 dB in a wide frequency range of 2.1–7.6 GHz and a gain of more than 10 dB with a peak of 11.7 dB. Over this range, a minimum NF of 3.4 dB and a relatively high IIP3 of greater than 10 dBm with a 15.7 dBm peak are achieved. The results indicate that the proposed technique effectively improves the linearity of the cascode LNA in a wide range of frequencies. At the same time, NF and gain performance are also improved.
In this paper, a new design method of the dual-band bandpass filter which consists of feed line with stepped-impedance resonator (SIR) structure, open-loop ring resonator (OLRR) with SIR, and uniform OLRR is proposed. The SIR structure which can control harmonic frequencies is used to provide the maximum magnetic coupling at the same positions of both the upper and lower feed lines, irrespective of the first passband and the second passband of the dual-band bandpass filter and improve characteristic of stopband between the first and second passbands. This proposed design method was confirmed to be useful from measured results for dual-band bandpass filter operated at 2.4 GHz and 5.5 GHz.