立体声10W模拟输入D类放大器

Cirrus Logic公司推出立体声10w模拟输入D类音频放大器ICCS3511，以拓展公司D类音频放大器产品线。CS3511包括有源媒体扬声器、底座、混合无线电、平板显示器以及迷你家庭影院系统等。     

低成本实现恒定开关频率的无滤波器D类音频放大器

本文提出了一种新的简单的无滤波器D类音频放大器。拟议的无滤波器D类音频放大器提供了同步3级PWM输出低和总成本低的的优势。此外,由于滞后窗口变化,可以获得PWM输出的恒定开关频率。     

D类功放在便携式设备中的应用

采用D类放大器可延长电池供电终端产品的工作时间,并产生更少的热量,因此高效率D类音频功率放大器正越来越多地被用在移动电话、智能电话,PDA及其他类似便携式应用中,以取代AB类放大器.简单陈述D类功放的构成及原理,并以TI公司的芯片TPA2012D2为例,着重介绍该芯片在便携式媒体播放器(PMP)中的应用实例.该例在实际应用中得到较好的音频播放表现.     

WMS温度测量中谐波信号锁相放大器的设计

在波长调制光谱技术(Wavelength Modulation Spectroscopy, WMS)温度测量中,传统的锁相放大器测量谐波信号的振幅必须对被测信号及参考信号的相位单独进行调整。针对这一问题,设计了一种基于高精度平衡调制器AD630进行同步相敏检测的谐波信号的双锁相放大器。与传统的锁相放大器相比,所提双锁相放大器利用正交双通道的平方和检测,可以避免被测信号与参考信号进行严格的相位匹配问题。利用Multisim软件构建仿真模型,包括前置高通滤波器、正交双通道的相敏检波器、低通滤波器等部分。理论计算和仿真结果表明,所提方法能够准确检测微弱一次、二次、四次谐波信号的幅度,检测误差小于5%,具有电路简单、运行速度快、线性度高等优点,能够满足WMS温度测量工程应用。     

是什么影响了功放的声音表现

几十年来,音频功率放大器的工作电路并没有太大的突破。无非还是A类、B类、AB类三种。虽然近年来数码技术发展很快,D类数字放大器得到一定的应用,但是,由于音质远远不及前三种放大器,所以目前应用最多的仍然是传统的放大器电路。即使是同一款电路,经不同设计师之手制作出     

单端A类放大器及场效应管（3）

4V-MOS场效应管单端A类功放的制作 设计放大器有两个基本原则：一是简单,二是线性。能做到最简单的放大器线路就是单端A类,简单不是单端A类放大使用的唯一理由,是因为单端A类最具有迷人的音乐感。     

超宽带SiGe HBT低噪声放大器的设计和分析

设计了一款具有电阻反馈的新型超宽带(UWB)SiGe HBT低噪声放大器(LNA).因为摒弃了使用占片面积大的电感,所以极大节省了放大器的芯片面积和制作成本.在新型放大器的反馈支路中,使用了复合分布式电阻和隔直流电容,代替了传统的单一电阻.用这种方式设计的LNA,仅通过调整与电容串联的电阻就可以极大地改善放大器的端口匹...     

掺铒光纤放大器(EDFA)的空间辐射效应分析

掺铒光纤放大器(EDFA)是光通信系统中的重要组成部件.介绍了掺铒光纤放大器(EDFA)的组成及其工作原理,并且分析了掺铒光纤放大器(EDFA)在空间应用中可能产生的辐射效应.为进一步开展其相关的试验研究工作提供了依据.     

带ESD保护的2.4GHz低噪声放大器的分析与设计

分析了静电放电(ESD)保护对源极电感负反馈低噪声放大器(LNA)的输入阻抗匹配和噪声匹配的影响。给出了带ESD保护的低噪声放大器在功耗限定的条件下同时满足功率匹配和噪声匹配的优化方法,基于该方法,采用0.18μm RF CMOS工艺设计了应用于无线传感网(WSN)的2.4GHz低噪声放大器。测试结果表明,低噪声放大器噪声系数(NF)为1.69dB,增益为15.2 dB,输入1 dB压缩点和输入三阶截点(IIP3)分别为-8dBm和1dBm,在1.8V电源电压下消耗电流3.1mA。     

基于降低电磁干扰专利技术的D类音频应用

D类放大器存在的电磁干扰问题,采用扩展频谱调制、调制拓扑、边沿速率控制、有源辐射限制等专利技术来降低EMI,在便携式系统中已得到广泛应用。     

D类功放中数字调制器的研究与实现

数字脉冲宽度调制(Digital Pulse Width Modulation,DPWM)结构简单、稳定性好,是主动声呐D类功放中常用的调制技术,但是它会产生信号失真和电磁干扰问题。针对主动声呐中D类功放的要求,设计了一种新的1.5bitΣ-Δ调制器。该调制器不仅能够改善DPWM存在的信号失真和电磁干扰问题,而且能够解决常规Σ-Δ调制器存在的高开关频率导致的高开关损耗问题。采用现场可编程逻辑门阵列(FPGA)对该调制器进行实现,在全桥D类功放上进行了实验验证。通过1.5bitΣ-Δ调制器和DPWM性能对比,表明该1.5bitΣ-Δ调制器适合主动声呐D类功放的应用。     

一种全桥式高功率放大器

用集成功率放大器驱动大功率三极管构成推挽功率放大器,两路推挽功率放大单元可以组合构成全桥式功率放大器,这种放大器大量使用大功率三极管等分立元件,能够提高电路总的额定功率,并且使元件布局分散有利于实现散热设计,工程样机研制证明该方法适用。水库测试结果表明:驱动某大型双谐振压电陶瓷换能器,功放样机输出连续信号时,在5 k Hz左右输出电功率达到1600 W以上。单频信号工作时观察信号波形,信号畸变与失真较小。根据试验与测试结果分析了末级三极管上的功率耗散情况,验证了工程样机在散热设计方面的有效性。     

Zigzag slabs for solid-state laser amplifiers: batch fabrication and parasitic oscillation suppression

We have developed a 100 W class Nd:YAG master oscillator power amplifier system based in part on an end-pumped zigzag slab power amplifier. This amplifier incorporates parasitic oscillation suppression by using roughened edges and achieves a small-signal gain coefficient (g(0)l) of 8.06. We describe a novel technique for suppression of parasitic oscillations using claddings on slab edges that significantly increases g(0)l to 11.63 and increases the single-pass extracted power in a power amplifier by 50%. Commercial use of these zigzag slab amplifiers has been limited by the time and cost of production. We describe a new batch fabrication technique that improves the quality and significantly reduces the cost of zigzag slabs.     

Merits of PM noise measurement over noise figure: a study at microwave frequencies

This paper primarily addresses the usefulness of phase-modulation (PM) noise measurements versus noise figure (NF) measurements in characterizing the merit of an amplifier. The residual broadband (white PM) noise is used as the basis for estimating the NF of an amplifier. We have observed experimentally that many amplifiers show an increase in the broadband noise of 1 to 5 dB as the signal level through the amplifier increases. This effect is linked to input power through the amplifier's nonlinear intermodulation distortion. Consequently, this effect is reduced as linearity is increased. We further conclude that, although NF is sometimes used as a selection criteria for an amplifier for low-level signal, NF yields no information about potentially important close-to-carrier 1/f noise of an amplifier nor broadband noise in the presence of a high-level signal, but a PM noise measurements does. We also have verified experimentally that the single-sideband PM noise floor of an amplifier due to thermal noise is -177 dBc/Hz, relative to a carrier input power of 0 dBm.     

Phase-noise reduction in surface wave oscillators by using nonlinear sustaining amplifiers

Nonlinear sustaining amplifier operation has been investigated and applied to high-power negative resistance oscillators (NRO), using single-port surface transverse wave (STW) resonators, and single-transistor sustaining amplifiers for feedback-loop STW oscillators (FLSO) stabilized with two-port STW devices. In all cases, self-limiting, silicon (Si)-bipolar sustaining amplifiers that operate in the highly nonlinear AB-, B-, or C-class modes are implemented. Phase-noise reduction is based on the assumption that a sustaining amplifier, operating in one of these modes, uses current limiting and remains cut off over a significant portion of the wave period. Therefore, it does not generate 1/f noise over the cut-off portion of the radio frequency (RF) cycle, and this reduces the close-in oscillator phase noise significantly. The proposed method has been found to provide phase-noise levels in the -111 to -119 dBc/Hz range at 1 KHz carrier offset in 915 MHz C-class power NRO and FLSO generating up to 23 dBm of RF-power at RF versus dc (RF/dc) efficiencies exceeding 40%. C-class amplifier design techniques are used for adequate matching and high RF/dc efficiency.     

Photoelectric amplifiers F17

Conclusions The photoelectric amplifiers F17 have no electronic tubes, they are simple and reliable. Their output power is sufficient to work normal indicating and ink recording instruments. When this power is inadequate other amplifying devices can be connected to them (electronic, magnetic and other amplifiers including electric motors) thus providing any output power that may be required in practice. The zero drift in such cases remains, as it was originally insignificant.The F17 photoelectric amplifiers should extend the use of photocompensation systems to various spheres of science and technology.     

Conceptual design of a 10 PW class laser with a hybrid amplification chain

We design a 10 PW class laser system with a hybrid amplification chain. The hybrid amplification chain with a total gain of 10(4) composed of Ti:chrysoberyl amplifiers and Ti:sapphire amplifiers. The ability of this hybrid amplifier chain to control gain narrowing and gain saturation is demonstrated by numerical simulations.     

Performance of two-stage discrete fiber Raman amplifiers with and without all-optical gain clamping

Using numerical simulations, we analyze the properties of two-stage discrete fiber Raman amplifiers without and with all-optical gain clamping. In both cases a two-stage amplifier can be designed to have the same gain characteristics as a single-stage amplifier with improved noise performance by use of either the same total length of gain fiber (but with increased pump power) or total pump power (but with increased total length of gain fiber).     

Cache Memory Design for Single Bit Architecture with Different SenseAmplifiers

Most modern microprocessors have one or two levels of on-chip caches to make things run faster, but this is not always the case. Most of the time, these caches are made of static random access memory cells. They take up a lot of space on the chip and use a lot of electricity. A lot of the time, low power is more important than several aspects. This is true for phones and tablets. Cache memory design for single bit architecture consists of six transistors static random access memory cell, a circuit of write driver, and sense amplifiers (such as voltage differential sense amplifier, current differential sense amplifier, charge transfer differential sense amplifier, voltage latch sense amplifier, and current latch sense amplifier, all of which are compared on different resistance values in terms of a number of transistors, delay in sensing and consumption of power. The conclusion arises that single bit six transistor static random access memory cell voltage differential sense amplifier architecture consumes 11.34 μW of power which shows that power is reduced up to 83%, 77.75% reduction in the case of the current differential sense amplifier, 39.62% in case of charge transfer differential sense amplifier and 50% in case of voltage latch sense amplifier when compared to existing latch sense amplifier architecture. Furthermore, power reduction techniques are applied over different blocks of cache memory architecture to optimize energy. The single-bit six transistors static random access memory cell with forced tack technique and voltage differential sense amplifier with dual sleep technique consumes 8.078 μW of power, i.e., reduce 28% more power that makes single bit six transistor static random access memory cell with forced tack technique and voltage differential sense amplifier with dual sleep technique more energy efficient.     

Nonlinearity estimation in power amplifiers based on subsampledtemporal data

In this paper we apply subsampling techniques to capture the temporal input-output relationship of RF power amplifiers. This approach avoids the distortion introduced by the upconverter and downconverter stages. We develop polynomial models with memory from the available data and evaluate their performance by estimating device parameters such as adjacent channel power ratio and AM-AM curves. The estimated parameters show good agreement with the empirical ones