A GHz Spintronic-Based RF Oscillator

A nano-sized oscillator for RF applications is presented which is based on two spintronic effects, the tunneling magnetoresistance (TMR) and the spin momentum transfer torque. The oscillation frequency is several GHz and can be tuned by both a DC bias current and an external DC magnetic field. High compactness, high tunability and full compatibility with standard CMOS process make this spin torque nano-oscillator (STNO) a promising candidate for future RF transceivers. The main issues to be addressed are spectral purity and output power. First measurements on a hybrid built connecting the STNO to a dedicated wideband amplifier show that today's performance in terms of power is close to but not yet compatible with telecommunication standard requirements. Using time domain analysis we show that frequency fluctuations are an issue for spectral purity. Frequency synthesis concepts based on STNOs are also discussed.     

Asymptotic Disturbance Rejection of the Duffing's System by Adaptive Output Feedback Control

This paper studies the output feedback disturbance rejection problem of the uncertain Duffing's system subject to a sinusoidal external disturbance with unknown frequency and amplitude. We first formulate the problem as a global robust output regulation problem subject to an uncertain exosystem which models the sinusoidal disturbance. Then, we apply the adaptive output regulation technique to construct an output feedback control law to solve the problem. Our adaptive control law contains a parameter update law for estimating the unknown frequency of the disturbance, and we will show that the estimated frequency converges to its real value.      

Multirate Sampling Method for Acceleration Control System

This paper focuses on the realization of high-performance motion control based on acceleration control. A disturbance observer is used to construct an acceleration control system. A high sampling frequency is known to be effective for improving the performance. Characteristics of acceleration control are investigated to discuss the relationship between the performance and a sampling frequency of the system. The needs for a high sampling frequency for an output are then described. Based on these considerations, a novel multirate sampling method for the acceleration control system is proposed. An output sampling period is set shorter than an input sampling period, and control calculation is executed at each output sampling period in the method. The disturbance observer is redesigned for application to the multirate system. Stability analysis is performed to verify the validity of the proposal. Feasibility of the proposed method and its influence on the performance are also verified by experimental results     

压控振荡器组件的改进设计

介绍了某导航设备频率合成器的原理。针对导航设备压控振荡器组件故障率高的缺点,对其进行了改进设计。设计中压控振荡器组件采用改进型电容三点式振荡电路,并对组件的实现方法进行了阐述。经过生产验证,新压控振荡器组件生产性好、调试量小、输出频率稳定、抗震性好、工作可靠、满足整机性能指标,完全可以替代原压控振荡器组件。     

Implementation of a high speed frequency synthesizer employing a dual input phase accumulator

We present a new PLL based frequency synthesizer, in which we have replaced the conventional phase frequency detector and the dividers (programmable counters) with a sequential dual input phase accumulator (DIPA), consisting of a digital circuit employing adders, registers and a ladder. The main feature of the DIPA is that the two input frequencies are not required to be normalized (divided down) to the step frequency of the synthesizer. Instead, the two different high frequencies, that is the reference and the output frequency of the synthesizer, are applied directly. The DIPA samples and normalizes their phases at very high rates, calculates their phase difference, producing an output that consists of a dc component proportional to the phase difference and harmonics of the two input high frequencies. These harmonics are high frequencies and can easily be rejected by a wide bandwidth filter of the loop, without affecting the high convergence speed of the loop. Moreover, these harmonics do not generate spurs near the output frequency. The resolution of the DIPA based synthesizer depends only on the length of the digital word of the DIPA, and its convergence speed depends on the lower of the two input frequencies. The output of the DIPA is a linear function of the phase difference of the two input frequencies and its dynamic range exceeds the limit of ±2π that governs the conventional phase detectors. Thus, the proposed frequency synthesizer based on the DIPA has low phase noise, no spurs nearby the output frequency, high resolution and fast convergence rate. Additionally, the output frequency can be digitally modulated under the control of the closed loop, either by phase or frequency modulation.     

Digitally controlled oscillator design with a variable capacitance XOR gate

A digitally controlled oscillator (DCO) using a three-transistor XOR gate as the variable load has been presented. A delay cell using an inverter and a three-transistor XOR gate as the variable capacitance is also proposed. Three-, five- and seven-stage DCO circuits have been designed using the proposed delay cell. The output frequency is controlled digitally with bits applied to the delay cells. The three-bit DCO shows output frequency and power consumption variation in the range of 3.2486-4.0267 GHz and 0.6121-0.3901 mW, respectively, with a change in the control word 111-000. The five-bit DCO achieves frequency and power of 1.8553-2.3506 GHz and 1.0202-0.6501 mW, respectively, with a change in the control word 11111-00000. Moreover, the seven-bit DCO shows a frequency and power consumption variation of 1.3239-1.6817 GHz and 1.4282-0.9102 mW, respectively, with a varying control word 1111111-0000000. The power consumption and output frequency of the proposed circuits have been compared with earlier reported circuits and the present approaches show significant improvements.     

E波段倍频放大模块设计

E波段是毫米波中非常重要的频段,也是较为缺乏研究的频段。E波段可三倍频至亚毫米波频段,其中220 GHz是大气吸收窗口,具有非常重要的研究价值。基于此,文中设计了一款E波段倍频放大模块,为220 GHz太赫兹发射机提供三倍频源信号,该模块输入频率为11.1~13.34 GHz,输出频率为66.6~80 GHz,输入功率为4~5 dBm,输出功率>18 dBm,增益>13 dB,具有较好的输出功率平坦度。该模块的成功研制为亚毫米波收发模块提供了功率源条件。     

基于全相位陷波器解析设计的啸叫去除

为了快速且精准地抑制助听器中的啸叫效应,该文提出一种中心频率可以精确控制的全相位有限脉冲响应(FIR)陷波器解析设计。首先,为了获得较高的陷波精度,引入了整数部分m和小数部分λ来控制陷波的中心频率。然后,设计了一个偶对称的闭式解析式来计算陷波器系数。最后,为了保证输出信号的连续性和线性相位,进行数据延拓和截取操作。该陷波器具有线性传输特性,避免了非线性失真。为了检验陷波器的滤波性能,将其应用在助听器中去除啸叫。实验结果表明,该滤波器在啸叫频率下的衰减值可达–330 dB,信噪比达22 dB,输出波形质量好,算法复杂度低,鲁棒性高,具有一定的应用前景。     

A Monolithically Integrated 12V/5V Switch-Capacitor DC-DC Converter

A monolithically integrated 12V/SV switch capacitor DC-DC converter with structure-simplified main circuit and control circuit is presented. Its topological circuit and basic operating principle are discussed in detail. It is shown that elevated operating frequency, increased capacitance and reduced turn-on voltage of the diodes can make the converter's output characteristics improved. Reducing resistance of the equivalent resistors and other parasitic parameters can make the operation frequency higher. As a feasible efficient method to fabricate monolithically integrated converter with high frequency and high output power, several basic circuits are parallelly combined where the serial-parallel capacitance is optimized for the maximum output power. The device selection and its fabrication method are presented. A feasible integration process and its corresponding layout are designed. All active devices including switching transistors and diodes are integrated together with all passive cells including capacitors and resistor on a single chip based on BiMOS process,as has been verified to be correct and practical by simulation and chip test.     

IPMC驱动材料控制系统的研制

新型驱动材料IPMC具有驱动电压低,输出位移大,柔韧性好等优点,在仿生机器人和医疗仪器等微驱动领域有巨大的应用前景。为了满足IPMC驱动的需要和实现其便携性,为此进行了控制系统的研制。该控制系统由ATmega16L单片机控制模块、D/A数模转换模块、扩大输出电流模块、电源模块、按键模块和LCD显示模块组成,能产生驱动IPMC双向摆动时所需的、具有高输出电流的双极性正弦波和方波,且其频率和幅值可调,同时还具有多通道分时控制功能。通过示波器对该控制系统的波形切换、调频和调幅功能进行的检测,也验证了其可行性。     

逆变器载波PWM方法的研究

多电平逆变器具有输出容量大、输出电压高、电流谐波含量小等优点,广泛应用于高速动车组、中高压变频调速、电力系统有源滤波等方面。文章对三电平二极管中点箝位式逆变器的中点电位平衡问题进行了分析,讨论了几种常用的载波PWM方法,并在此基础上提出了一种新的将相位偏移、注入零序分量相结合的PWM法。仿真结果证明新方法有良好的中点电位控制能力及输出电压谐波特性。     

Waveform shaping of chirp-controlled signal by semiconductoroptical amplifier using Mach-Zehnder frequency discriminator

The optical output waveform of a semiconductor optical amplifier (SOA) is shaped using a Mach-Zehnder interferometer (MZI) as a frequency discriminator in order to suppress its distortion at high SOA input powers. This technique is applied to chirp control of an optical signal using an SOA, and the chirp control with waveform shaping greatly improves the transmission performance of a positively chirped optical signal in standard single-mode fiber over a wide range of SOA input powers. We also demonstrate that the chirp control with waveform shaping can be achieved without changing the drive settings of the SOA and MZI, even when the optical frequency is switched to another channel located on the wavelength-division-multiplexing frequency grid     

Digitally controlled oscillator

A monolithic integrated digitally controlled oscillator circuit is discussed. The oscillator has an output frequency range from 19.07 Hz to more than 20 MHz with a resolution of 19.07 Hz. It is fully linear over the complete control range with respect to the digital control word, has the long-term stability of a quartz oscillator, and the output clock edge uncertainty has a standard deviation of less than 0.5 ns. The circuit requires only a reference quartz as an external component. It operates from a single 5-V power supply, is fabricated in a 1.5-μm double-metal single-poly standard CMOS process, and requires an area of 4.1 mm²     

A Monolithically Integrated 12V/5V Switch-Capacitor DC-DC Converter

Motivated by the battery-operated applications that demand compact,lightweight andefficient DC-DC converters,many kinds of converter circuits have been published.Amongthem,resonantconverters and the soft-switching convertershave greatl...     

用于电子负载的变频单周控制器的研究

对中小功率的电子负载的研究,重点主要集中在拓扑结构和控制策略两个方面。针对传统定频单周控制在控制两级变换型电子负载中存在的问题,文章运用反馈电压调节单周控制器的工作频率,提出了变频单周控制策略,较好地解决了输出波形畸变和控制失稳的问题,并通过实验验证了所提改进控制策略的有效性。     

An Externally Powered, Multichannel, Implantable Stimulator for Versatile Control of Paralyzed Muscle

Through the use of semicustom integrated circuit technology, an implantable muscle stimulator has been developed. The unit is small, lightweight, has low power consumption, and is intended for permanent usage. The stimulator circuitry is externally controlled and powered by a single encoded radio frequency carrier. Up to eight independently controlled stimulus output channels are provided, with output channel selection, stimulus pulse width, and stimulus pulse frequency under external control. A constant current biphasic stimulus pulse is used, in which the stimulus current amplitude can be preset by a single resistor value. The stimulator circuitry has been implemented in thick film hybrid form, and has undergone laboratory evaluation for 48 months.     

高精度DPSS倍频激光器数字温控系统的设计

温度影响着典型的小型化半导体泵浦固态（DPSS）倍频激光器输出模式和激光功率。为获得稳定的倍频激光横模和输出功率,应用温度传感器、ADC和DAC集成的微处理器芯片,以及半导体致冷器（TEC）,设计开发了高精度DPSS倍频激光器数字温控系统。其结构紧凑、使用方便,温度不稳定度可达±0．05℃。通过改进PID算法的程序控制,避免了积分饱和,同时也加快了系统恒温的速度。     

GaAs Dual-Gate FET for Operation Up to K-Band

A high-frequency equivalent circuit model of a GaAs dual-gate FET and analytical expressions for the input/output impedances, transconductance, unilateral gain, and stability factor are presented in this paper. It is found that the gain of a dual-gate FET is higher than that of a single-gate FET at low frequency, but it decreases faster as frequency increases because of the capacitive shunting effect of the second gate. A dual-gate power FET suitable for variable gain amplifier applications up to K-band has been developed. At 10 GHz, a I.2-mm gatewidth device has achieved an output power of 1.1 W with 10.5-dB gain and 31-percent power-added efficiency. At 20 GHz, the same device delivered an output power of 340 mW with 5.3-dB gain. At K-band, a dynamic gain control range of up to 45 dB was obtained with an insertion phase change of no more than +-2 degrees for the first 10 dB of gain control.     

A 2 W CMOS Hybrid Switching Amplitude Modulator for EDGE Polar Transmitters

This paper presents a hybrid switching amplitude modulator for class-E2 EDGE polar transmitters. To achieve both high efficiency and high speed, it consists of a wideband buffered linear amplifier as a voltage source and a PWM switching amplifier with a 2 MHz switching frequency as a dependent current source. The linear amplifier with a novel class-AB topology has a high current-driving capability of approximately 300 mA with a bandwidth wider than 10 MHz. It can also operate on four quadrants with very low output impedance of about 200 at the switching frequency attenuating the output ripple voltage to less than 12 . A feedforward path, a PWM control, and a third-order ripple filter are used to reduce the current burden of the linear amplifier. The output voltage of the hybrid modulator ranges from 0.4 to 3 V for a 3.5 V supply. It can drive an RF power amplifier with an equivalent impedance of 4 up to a maximum output power of 2.25 W with a maximum efficiency of 88.3%. The chip has been fabricated in a 0.35 m CMOS process and occupies an area of 4.7 .     

用于红外气体检测的高稳定性DFB激光器驱动电源

为了满足红外气体检测对高性能激光器驱动电源的要求,文中采用PID控制算法,设计并研制了一款高稳定的DFB激光器驱动电源。其硬件主要包括信号产生模块、压控恒流源模块、电路保护模块,具备输出电流保护功能。信号产生模块主要通过DDS产生正弦波,再通过比较器产生方波,同时采用DA转换技术实现直流波、三角波、锯齿波的输出。控制方案上采用PID算法,通过深度负反馈控制,实现高稳定电流输出。利用此驱动电源对中心波长为1 563.09 nm的DFB激光器进行驱动实验。结果表明,所研制的驱动电源具有输出波形类型、幅度和频率三者数控可调的功能,电流幅度范围为0~1 A;正弦、方波频率范围为1 Hz~1 MHz,三角、锯齿、直流波频率范围为1 Hz~100 Hz,频率分辨率为1 Hz;输出电流线性度为99.93%,长时间输出电流稳定度为0.019 7%。