Power Amplifier for an Optical Modulator

A power amplifier is described in which, in order to combine the powers of channel amplifiers, directional couplers are used that are based on helical transmission lines placed in a cylindrical shield. The amplifier maximum output power is 200 W, the passband is 154–170 MHz, and the gain is 18 dB. The amplifier withstands a sudden prolonged load disconnection or short-circuiting when high-power (as high as 100 W) signals are applied to its input.     

A Bandpass Power Amplifier for 60–70 MHz

A bandpass power amplifier is described in which ring combiners (adders) designed from lumped components are used for combining the powers of channel amplifiers. The amplifier performance data are as follow: the maximum level of the output power is no less than 140 W, the passband is 60–70 MHz, the gain is 12 dB, and the power supply voltage is 13.8 V.__________Translated from Pribory i Tekhnika Eksperimenta, No. 4, 2005, pp. 47–50.Original Russian Text Copyright © 2005 by Titov.     

A Low-Consumption Ultrabroadband Power Amplifier with the Overload Protection

An ultrabroadband power amplifier with automatic control of the consumption current intended for operation into an unmatched load is described. To control the amplifier consumption current and gain, voltage sensors and output-current sensors are used at the amplifier output. The amplifier passband is 20–240 MHz; gain flatness, ±1.5 dB; gain, 40 dB; maximal output power, 20 W minimum; consumption current under no-signal condition, 2.2 A; and under peak-load conditions, 6.8 A.     

A Two-Channel Power Amplifier with a Diplexer Output

To sum up the powers of two independent signals from a two-channel amplifier, a diplexer constructed with the use of small-sized directional couplers is used. The level of the intermodulation components of the output spectrum is decreased down to –60 dB. The output power of the signals is 10 and 75 W, respectively; the gain of the channel amplifiers is 40 dB; and the amplified signals are the video and audio signals of the TV channel 12.     

A Picosecond DC Amplifier

A picosecond dc amplifier with a multichannel frequency division is described. The basic characteristics of the amplifier are as follows: the gain is 26 dB, the pass band is 0–5.6 GHz, the nonuniformity of the amplitude–frequency response is ±1.5 dB, the amplitude of the output voltage is ±2V, the rise time of the step response is 70 ps, and the amplified pulse duration is not limited.     

Double-pass tapered amplifier diode laser with an output power of 1 W for an injection power of only 200 μW

A 1 W tapered amplifier requiring only 200 μW of injection power at 780 nm is presented in this paper. This is achieved by injecting the seeding light into the amplifier from its tapered side and feeding the amplified light back into the small side. The amplified spontaneous emission of the tapered amplifier is suppressed by 75 dB. The double-passed tapered laser, presented here, is extremely stable and reliable. The output beam remains well coupled to the optical fiber for a timescale of months, whereas the injection of the seed light did not require realignment for over a year of daily operation.     

High power solid state rf amplifier for proton accelerator

A 1.5 kW solid state rf amplifier at 352 MHz has been developed and tested at RRCAT. This rf source for cw operation will be used as a part of rf system of 100 MeV proton linear accelerator. A rf power of 1.5 kW has been achieved by combining output power from eight 220 W rf amplifier modules. Amplifier modules, eight-way power combiner and divider, and directional coupler were designed indigenously for this development. High efficiency, ease of fabrication, and low cost are the main features of this design.     

重复频率锁定的783 nm飞秒光纤激光器研制

设计并搭建了重复频率长时精确锁定的783 nm飞秒光纤激光器。该激光器基于全保偏非线性干涉环镜(NALM),实现掺铒光纤振荡器锁模脉冲输出,由与脉冲分离器级联的环境稳定掺铒光纤双级放大器进行功率放大,实现了平均功率1.30 W、脉冲宽度130 fs、重复频率77.1 MHz、1 560 nm脉冲输出;通过周期极化铌酸锂(PPLN)光学晶体倍频,获得了平均功率为0.52 W、脉冲宽度为140 fs、783 nm脉冲输出。通过重复频率监测及锁相环技术,进一步将掺铒光纤振荡器的重复频率溯源至参考铷原子钟,12 h内频率抖动峰-峰值为5 mHz、标准偏差为1.2 mHz。该激光器系统具有稳定性高、集成度高、体积小的特点。     

ICP仪器中大功率射频固态功率放大板的设计

本研究提出了一种在电感耦合等离子体(ICP)质谱/光谱仪中,安装在离子源光炬前端,单板最高功率可达2000 W的射频功率放大板的设计制作方法。该放大板采用最新射频横向扩散金属氧化物半导体（LDMOS）管Freescale MRFE6VP61K25H为末级放大器。MRFE6VP61K25H单管放大能力可达1250 W,改进后单板通过2个LDMOS管组成推挽并行式的E类放大器,可轻松达到ICP光源要求的1600 W设计功率。该放大器的成品体积为所用装备的25%,制造成本也仅为目前同类产品的50%,达到了体积小、造价低、功率大的设计效果。此设计可为进一步研制便携式ICP质谱/光谱仪等提供良好的硬件基础。     

L波段雷达功率放大器设计和优化

设计一种L波段雷达功率放大器。对功率放大器的输出功率、脉冲顶降、热设计等关键参数进行了理论分析,结合电路输出功率的仿真结果对功率放大器的工作效率以及输出功率的带内波动进行评估。研究了脉冲顶降对输出信号的品质影响,探讨了功率放大器热设计的半定量的制约问题。给出系统主要参量的优化设计方法,完成了L波段雷达功率放大器的样机制作。在极限温度下对功率放大器的输出功率、脉冲顶降、脉冲上升下降时间、功率谱主副瓣功率比以及主杂波功率比等频域特性参数进行了测试与优化。测试结果表明,在极限温度范围下,系统主要技术指标不受温度的影响。与国内外同类产品相比,该功率放大器具有体积小、可靠性高、效率高、稳定性好等特点,同时较低的相位噪声有利于提高接收机的灵敏度。因此,该L波段雷达功率放大器可广泛应用于民用和军用雷达领域,具有很好的应用前景。     

基于C8051F的交流功率放大系统

以C8051F单片机为核心的交流功率放大系统的设计,采用C8051F内部的电压方式D/A转换器输出0～1V的正弦波,用于控制功率放大器输出电压按设定值变化.同时功率放大系统具有过流保护、过压保护与过热保护功能、输出电压稳定、带载能力强、控制精度高等特点.     

A Modulation Driver of Quasi-sinusoidal Asymmetric Current

A modulation driver of quasi-sinusoidal asymmetric current designed to feed an electrocoagulator is described. The device ensures specified parameters of the output current for a wide range of load resistances and frequencies. The rated load power is 2.5 kW, the output current has a quasi-sinusoidal asymmetric shape, the mean value of the current positive half-wave is 5–16 A, the degree of asymmetry of half-waves of opposite polarities is 6–11, the range of the sliding frequency control is 20–2000 Hz, and the frequency set-on accuracy is ±1 Hz. The device is fed from a 380 V⁺¹⁰ _–15% and (50–60)-Hz three-phase main.     

比例电磁铁推拉储能式PWM功放电路

针对传统脉冲宽度调制(Pulse Width Modulation,PWM)功放电路难以满足大功率高频响比例电磁铁线圈快速充放电要求的问题,提出一种基于推拉储能原理的PWM功放电路。在比例电磁铁功放电路中设置储能模块,当线圈需要快速充电时,储能模块释放能量,补充供电电源电流输出;当线圈需要快速放电时,储能模块充电吸收能量,从而缩短线圈的充放电时间。针对功率79 W、额定电流3.3 A的某比例电磁铁线圈进行仿真分析和实验,研究表明:相比传统的反接卸荷式功放电路,该推拉储能式PWM功放电路充电时间缩短24%,放电时间缩短45%,显著提高了大功率比例电磁铁的响应速度。     

A Megavolt Nanosecond Generator with a Semiconductor Opening Switch

A high-current nanosecond-pulse generator with a pulse power of up to 1.6 GW, an output voltage of 0.5–1 MV, pulse duration of 40–60 ns, and repetition rates of 300 Hz (in a steady-state mode) and up to 850 Hz (in a burst mode) is described. Its average output power is 30 kW at a pulse repetition rate of 500 Hz. The energy-switching system of the generator fully consists of solid-state elements: a thyristor, magnetic switches, and a semiconductor-opening switch based on SOS diodes.     

A Multifunctional Microwave Gunn Oscillator for Magnetic Resonance Spectroscopy Applications

A waveguide Gunn oscillator operating in the 12-mm wavelength range, in which the gyromagnetic frequency tuning is carried out using a FeBO₃ antiferromagnetic single crystal, is described. To increase the output power, the pulsed power supply of the Gunn diode is employed. In the case of a microwave pulse duration of 0.1–50 s and off-duty factor of no less than 200, the pulse output power reaches 1.3 W (in the continuous mode, it is 0.3 W). The generator is developed for magnetic resonance spectroscopy applications in order to solve a wide circle of problems, including investigations of the nonlinear spin dynamics of magnetic materials and study of spectra of optical magnetic-resonance detection.     

基于LCP径向偏振光输出的掺镱MOPA脉冲光纤激光器

为实现光纤激光器径向偏振光的高效输出,提出并搭建了基于液晶聚合物(LCP)的纳秒脉冲掺镱(Yb)主振荡器功率放大(MOPA)系统。该系统采用空间相位转换法,利用LCP涡旋半波片将全光纤MOPA激光器输出的高峰值功率、窄线宽、线偏振、高斯形分布的纳秒脉冲信号转换为横向强度呈空心环状分布的拉盖尔-高斯光。MOPA激光器系统由窄线宽连续种子源、电光强度调制器和后续的5级YDF放大器组成,通过实验获得了20.1 W的稳定LP01模输出。而后的LCP涡旋波片用作空间模式转换器,最终获得的平均输出功率为19.5 W,脉宽为10 ns,重复频率为10 kHz,横向剖面呈规则空心环形的径向偏振光输出,模式转换效率可达97%。另外,通过PBS测量法测得径向偏振光的模式纯度约为88.5%,兼具高功率与高纯度的优势。     

A Low-Pressure Excimer Light Source for a Spectral Region of 170–310 nm

A low-pressure excimer light source pumped by a longitudinal dc glow discharge operates on the B–X and D–X transitions of Ar, Kr, and Xe chlorides and on the D–A transition of chlorine molecules. The output characteristics of a source with a discharge region 100 mm long and an inner diameter of the discharge tube of 5 mm were optimized on Xe(Kr, Ar)/Cl₂, Ar/Kr/Cl₂, Ar/Xe/Cl₂, and Kr/Xe/Cl₂ mixtures. The light source operated within a spectral range of 170 to 310 nm. The average radiation power and operation efficiency were 1.8–8.2 W and 21%, respectively.     

基于DDS的现场校验仪变频功率源研究

为满足互感器现场检定系统的需要,设计并实现了一种程控变频功率源,该功率源以FPGA芯片为核心,采用直接频率合成技术(DDS)产生频率可调的正弦波信号,其输出频率范围为1~200 Hz,精度优于0.05 Hz;功率放大电路部分采用甲乙类双电源互补对称功率放大电路,实现较大的输出容量和高的线性度。     

电磁轴承中PWM开关功率放大器的实现

在电磁轴承中为了提高功率放大器的效率,一般采用PWM开关功率放大器。功率放大器控制电磁轴承中电磁铁线圈的电流,以获得轴承悬浮所需要的吸力。因此,电磁线圈电流的控制精度和速度将直接影响电磁轴承的悬浮特性。功放设计中,以电流型PWM控制器UC3842为控制核心,产生控制模拟开关通断时间的PWM信号;采用新型的高侧电流传感器AD628检测电磁线圈中的电流,并进行放大作为反馈信号,所设计的PWM开关功放应用于磁悬浮轴承中,其控制精度和速度达到了磁轴承悬浮的应用要求。     

Switching Possibilities of Reverse Switched-on Dynistors and Principles of RSD Circuitry (Review)

The results of studies of reverse switched-on dynistors (RSDs) intended for use in high-power pulse and converting devices are generalized. The basic principles of designing high-power RSD switches are analyzed. The main circuit designs of pulse and high-frequency RSD-based devices are described. The results of tests of high-voltage microsecond and submicrosecond pulse RSD generators with a pulse power of 10⁸–10¹⁰ W and high-frequency RSD inverters with a mean power of 10⁴–10⁵ W are presented.