中等数据率无线通信的实用解决方案(下)

ＲＦ收发器设计 ＲＦ收发器的框图示于图２。系统的要求如下： １．频带９０２～９２８ＭＨｚ,低功率（＜０ｄＢｍ）传输,直接变换ＦＭ。 ２．数据率 ５７．６ｋｂｉｔｓ／Ｓ,全双工。 ３．数据译码／编码－ＡＭＩ。 ４峰值频偏－８０ｋＨｚ。 ５．ＲＦ带宽－３３０ｋＨｚ。 ６．信道数－５。 ７．信道间隔－５００ｋＨｚ。 ８．接收器第－ＩＦ频率－７３．７ＭＨｚ。 ９．接收器第二 ＩＦ频率－１０．７ＭＨｚ。 １０．基准频率一１１．２ＭＨｚ, ± １０ｐｐｍ,１００ｋＨｚ内部频率。 １１．收发信道δ－２１．９ＭＨｚ。 １２．系…     

顶部超平SAW滤波器的研制及其在频率捷变模拟系统的应用：频率捷变信 …

频率范围在１０ＭＨｚ至３ＧＨｚ快速捷变信号的研制基于对１４－５８ＭＨｚ的信号的直接数字合成。在基带信号转化为中心频率为３０４ＭＨｚ，利用已实现的高性能声表面波滤波器来提高ＩＦ滤波。４４ＭＨｚ宽滤波器典型的能带波纹小于０．４ｄＢ（峰对峰），三次行程，电磁耦合和其它乱真信号被抑制为５０ｄＢ，电路，ＳＡＷ滤波器及其封装被精心设计成能够得到这种特性。     

SFM001宽带放大器

ＳＦＭ００１宽带放大器是由信息产业部电子第二十四研究所正向设计的电路。该电路具有噪声小、功耗低、动态范围大、增益高及增益;控制能力强等特点。它作为中频宽带放大器,可广泛用于雷达、通讯、仪器仪表等设备上。 主要技术指标：电源电流 ＩＣＣ：≤２２ ｍＡ,中心频率：１７．８～１８． ２ ＭＨｚ,３ ｄＢ带宽 ＢＷ：５～６ ＭＨＺ,增益 ≥７５ ｄＢ,ＡＧＣ控制范围,噪声系数 ＮＦ：≤２ ｄＢ,限幅输出,受控 ３ ｄＢ带宽 ＢＷ（３ ｄＢ）：≥４ ＭＨｚ。 该电路具有噪声小、功耗低、动态范围大,增益高及增益能力强等特点。…     

半导体和IC

半导体和ＩＣ１４位２ＭＨｚ取样Ａ／Ｄ转换器　　　　　　　查询号２３１Ｄａｔｅｌ公司的ＡＤＳ－９１９是一种高性能１４位２ＭＨｚ取样Ａ／Ｄ转换器，可按照奈奎斯特频率对输入信号进行取样而无遗漏码。ＡＤＳ－９１９具有优异的动态性能，信噪比为７７ｄＢ，总谐波失真为－７４ｄＢ。这种功能完备的ＡＤＳ－９１９采用２４脚ＤＤＩＰ封装，具有快速建立取样保持放大器、Ａ／Ｄ转换器、精密电压基准、定时／控制逻辑和纠锗电路。数字输入和输出电平为ＴＴＬ。ＡＤＳ－９１９采用±１５ｖ（±１２Ｖ）和＋５Ｖ电源，功耗为１．８Ｗ（±１…     

SH333小型化高增益中频放大器

３Ｈ３３３小型化高增益中频放大器是信息产业部电子第二十四研究所正向设计,并采用 ＳＭＴ技术进行工艺组装的微电路模块,具有低噪声、高增益、大动态、大封闭量和良好的选择性等特点。其主要作用是处理接收到的脉冲调制中频信号。 其主要技术指标：中心频率ｆ。：２９．８～３０．１ＭＨｚ,带宽 ＢＷ：３５． ９～６．２ ＭＨｚ,带内不平度Ａｖ：０． ３～０． ７ ｄＢ,带外衰减 ＳＳ：４３～４５ ｄＢ,总增益 Ａｖ：８０． ４～８４． ４ ｄＢ,噪声系数 ＮＦ：１． ２～１． ９ｄＢ,ＡＧＣ范围 ＭＡＧＣ：４８～５２ ｄＢ,封闭…     

PCS用PA驱动器

由于ＰＣＳ日益普及,使得对ＰＣＳ 频段高性能ＲＦ ＩＣ的需求增加。ＰＣＳ频段的发送和接收频率分别规定为１８５０－１９１０ＭＨｚ和 １９３０～１９００ＭＨｚ。当移动手机正在发送时,发送和接收频段邻近导致接收干扰,因此增加接收器的噪声功率。为降低噪声功率和改善隔离,大多数发送器系统设计在ＰＡ（功率放大器）驱动器和ＰＡ之间采用ＳＡＷ（表面声波）滤波器。然而,在ＰＣＳ发送频段中心频率的典型ＳＡＷ滤波器只提供大约１５ｄＢ接收频段衰减。这种低衰减导致在接收器前端可观的发射器噪声干扰。为解决此问题,系统设计人员…     

2.30GHz—2.70GHz锁相环式频率综合技术研究

本文阐述了一个基本的Ｓ波段锁相式频率综合器，频率范围是２．３０ＧＨｚ－２．７０ＧＨｚ，频率步进为５ＭＨｚ，相位噪声指标为￡（１０ｋＨｚ）〈－９５ｄＢｃ／Ｈｚ，杂散抑制优于５０ｄ，输出功率大于１０ｄＢｍ。     

混合集成低噪声宽带AGC放大器

采用厚膜混合集成工艺，研制出ＳＨ３０９－１低噪声宽带ＡＧＣ放大器，其噪声系数≤１．５ｄＢ，最大输入电平≥４００ｍＶ／５００Ω，增益≥５０ｄＢ，增益控制范围≥５０ｄＢ，工作频率范围为６０ＭＨｚ±１０ＭＨｚ。主要介绍了其设计原理及应用。     

声表面波大带宽滤波器的设计

报道在Ｙ旋１２７．８６°Ｘ传ＬｉＮｂＯ＿３基片上采用１／８λ＿０，５／８λ＿０结构的切指加权换能器的声表面波滤波器，成功地研制了中心频率为４０ＭＨｚ，３ｄＢ带宽为２０ＭＨｚ，矩形系数（Δｆ＿４０ｄＢ／Δｆ＿３ｄＢ）为１．４８，带内波动＜１．２ｄＢ，带外抑制＞４０ｄＢ．插入损耗＜３８ｄＢ，相对带宽（Δｆ＿－３ｄＢ／ｆ＿０）大于５０％的滤波器。     

高性能PCS双工器

Ｋ&ＬＭｉｃｒｏｗａｖｅ推出了ＷＳＤ-００１３２／００１３３／００１３４型高性能ＰＣＳ双工器。这三种型号的接收频段分别为１８５０～１８７０ＭＨｚ、１８７０～１８９０ＭＨｚ和１８９０～１９１０ＭＨｚ,它们的发射频段分别为１９３０～１９５０ＭＨｚ、１９５０～１９７０ＭＨｚ和１９７０～１９９０ＭＨｚ。接收带内的插入损耗小于１．５ｄＢ,发射带内的插入损耗小于０．９ｄＢ;所有带内的回波损耗最小为１４ｄＢ,可额定发射１０ＷＣＷ和１００ＷＰＩＰ（瞬时功率）。工作温度范围为０～５０℃,大小为１０６．７ｍｍ×６３．５ｍ…     

GHz频带声表面波谐振器的研究

本文叙述了GHz频带声表面波谐振器的设计、制造和试验结果.对两种不同模式的声表面波谐振器进行了研究,它们是瑞利波型谐振器和表面横波型谐振器.对两种波型谐振器的频率温度特性进行了比较.最后对表面横波(STW)谐振器在振荡器中的应用进行了研究.     

Surface transverse wave based FM modulator/demodulator

An FM modulator/demodulator system employing three identical surface transverse wave (STW) resonators is described. It operates at a centre frequency of 1012 MHz and can transmit data at over 100 kbit/s. This low cost system has a low noise and can detect FM signals with a deviation of less than 0.1 ppm.<>     

A Low Phase-Noise Voltage-Controlled SAW Oscillator With Surface Transverse Wave Resonator for SONET Application

A surface transverse wave (STW) resonator-based oscillator was developed in response to SONET OC-48 application. To meet the low jitter objective, a high-Q STW resonator was designed and fabricated in this study. The residual phase-noise measurement techniques are used to evaluate the feedback oscillator components, such as the loop amplifier, STW resonator, and electronic phase shifter, which can play important roles in determining the oscillator's output phase-noise spectrum. The oscillator's white phase-noise floor is -170dBc/Hz for carrier-offset frequency greater than 1 MHz. The oscillator's phase-noise level is -67dBc/Hz at a 100-Hz carrier offset. Both low close-in phase-noise and low white phase-noise floor makes the oscillator meet low jitter requirement. The electronic frequency tuning range exceeds plusmn200ppm. The oscillator provides 13.5 dBm of output power and consumes 65 mA from +5-V power supply     

声表面波器件的封装技术及其发展

目前各种声表面波器件的工作频率涵盖30MHz到3000MHz的频率范围,其封装形式主要有塑料封装、金属封装(如F11、TO-39)和sMD封装。在本文中,作者对声表面波器件的这三种主要封装形式对声表面波器件电传输性的影响作了系统的实验研究与分析,并论述了声表面波器件在封装方面的现状及其发展趋势。     

Epitaxially grown GaN thin-film SAW filter with high velocity andlow insertion loss

This study proposes GaN thin film as a piezoelectric material for SAW (surface acoustic wave) filters. Highly piezoelectric GaN film with a good surface morphology (RMS roughness =0.7 nm) was obtained on a 2-in (0001)-oriented sapphire substrate by MOCVD growth. The fabricated GaN SAW filter exhibited a very high velocity of 5803 m/s and relatively low insertion loss of -7.7 dB, The attenuation of the center frequency was about 22 dB smaller than those at the tops of the first sidelobes. When the wavelength of the IDT electrode was 60 μm (λ/4=15 μm), the center frequency was measured at 96.6 MHz, thereby facilitating a ~GHz operation when the IDT geometry is designed on a 1 μm scale. The calculated electromechanical coupling factor (K²) was about 4.3±0.3% which is larger than those obtained from other thin film piezoelectric materials and allows the realization of wider filter fractional bandwidths. TCF (temperature coefficient of frequency) was measured as low as -18.3 ppm/°C in the range from -25 to 50°C. These superior characteristics demonstrate that epitaxially grown GaN thin film can be successfully used for high performance SAW filters     

高频高阻带抑制极窄带声表面波滤波器

该文介绍了一种双声通道纵向耦合结构的高频高阻带抑制极窄带声表面波滤波器。利用有限元仿真研究了AT石英材料上高声速的声表面横波与浅体声波的激励情况,并进行了浅体声波抑制研究。通过调节叉指换能器金属化比,大幅降低了浅体声波对滤波器阻带抑制的影响,并制作出中心频率为1 220 MHz,插入损耗为5 dB、1 dB带宽700 kHz、阻带抑制50 dB的低损耗高阻带抑制极窄带声表面波滤波器。     

电磁寄生参数在高频SAW滤波器设计中的应用

在设计高频声表面波(SAW)滤波器的过程中,若只考虑封装壳和键合线的电磁寄生参数而忽略汇流条的电磁寄生参数,则SAW滤波器的实际性能易受汇流条寄生参数影响而出现通带波动和驻波增大等问题。该文拟用电声-电磁联合仿真方法设计高频SAW滤波器以解决汇流条寄生参数对SAW滤波器性能的影响。通过此方法研制的滤波器通带插入损耗小于1 dB,波动0.5 dB,通带内驻波最大值2.1,-1.5 dB带宽75.7 MHz,-3 dB带宽84 MHz (相对带宽为4.8%),-30 dB带宽112 MHz,BW_{-3 dB}/BW_{-30 dB}矩形系数1.33。包含封装壳、键合线及汇流条的寄生参数的理论仿真结果与实验测试结果吻合较好,表明了采用此模型设计高频SAW滤波器的可行性。     

Integrated optic strip waveguide phase modulator driven by a SAW

Single-mode integrated optic strip waveguide phase modulators driven by a surface acoustic wave (SAW) are investigated theoretically and experimentally. Evaluating the overlap integral, a good agreement is obtained between measured and theoretical results. Measurements were performed onZY-LiNbO3(z-cut crystal,y-propagating SAW) between 20 MHz and 580 MHz atlambda_{0} = 0.85 mum optical wavelength using Titanium indiffused waveguides. At 9-mW SAW power in an interaction length of 4 mm, optical phase shifts are measured to be 0.32 and 0.112 for TM and TE polarization, respectively, at 21.5 MHz.     

Electromechanical-Filter-Based Bandpass Sigma–Delta Modulator

This brief proposes an electromechanical-filter-based continuous-time (CT) bandpass (BP) sigma-delta modulator for wideband digitization at high intermediate frequency (> 70 MHz). Both the mechanically coupled microelectromechanical system and the longitudinally coupled surface acoustic wave (SAW) filters can be employed as loop filters. The advantages of the electromechanical filter are its low power consumption and accurate center frequency without the need for tuning. As a proof of concept, a fourth-order BP sigma-delta modulator is demonstrated with a 110-MHz SAW filter. Realized in a 0.35- mum SiGe heterojunction-bipolar-transistor bipolar complimentary metal-oxide-semiconductor technology, the prototype chip is clocked at 440 MHz and achieves 65-dB DR and 60-dB SNDR over 1 MHz, as well as 58-dB DR and 53-dB SNDR over the 3.84-MHz signal band. The total power consumption is 57 mW under a 3-V supply.