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介绍了一种GaN 功率器件调制电路的设计方法。该调制电路广泛用于T/ R 组件发射链路的大功率
GaN 功放,具有高电压工作、大电流供给以及尖峰电压抑制等功能。文中重点论述了调制电路的原理,指出尖峰电
压抑制功能是实现该调制电路的难点。经仿真分析实现了延时在500 ns 以内、负压检测电平在-4. 2~ -3. 8 V 的关
键指标。最后选用聚四氟乙烯印制板设计出GaN 功率器件调制电路实物,在T/ R 组件中进行了应用验证,测试结果
与仿真结论相符。该调制电路体积小、可靠性高,可用于高功率GaN 功放的设计,具有广阔的工程应用前景。 相似文献
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设计了一种温度不灵敏的高线性度的射频功率放大器芯片,采用新颖的带温度反馈环路的有源片上自适应偏置电路,该电路降低了温度引起的放大器集电极直流电流分量的变化量,补偿了由温度变化而引起的性能偏差,进而有效提高了放大器的线性度。基于这个温度不灵敏的偏置结构采用InGaP/GaAs HBT工艺设计了一个工作在2110~2170 MHz频段的功率放大器。测试结果表明,该功放在工作频段内的增益大于等于35.3 dB;在中心频率2140 MHz处,1 dB功率压缩点大于33 dBm,功率附加效率在输出功率24.5 dBm时为18%;使用LTE_FDD调制信号,获得邻信道功率比为-47 dBc。在环境温度为-40℃、+25℃和+80℃条件下,功放的增益平坦度较好,增益变化量小于1.5 dB,输出级集电极电流基本不变,有效降低了功放对温度的敏感性。 相似文献
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D类音频功放具有高效率的优点,但是随着功率的不断提高,通常需要完善的保护及限制电路。设计介绍了一种用于高功率D类音频功率放大器的输出功率调节电路,可以通过芯片外部引脚输入电压或编程的方式动态调节功放的输出功率。控制方式采用了限制输入信号最大幅度的方法,分别介绍了电路的控制原理与电路实现。测试结果显示,该电路达到了较好的调节效果,具有好的调节线性度,提高了高功率放大器电路的可靠性。 相似文献
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非线性功放对数字调制信号的影响研究 总被引:1,自引:1,他引:0
功放的非线性会带来调制信号的性能恶化,基于simulink建模,对比仿真了恒包络调制MSK和非恒包络调制BPSK,在功放线性和非线性区域时的误码性能,以及在带宽受限条件下,相邻信道干扰对信号误码性能影响.仿真结果表明,功放饱和对非恒包络调制信号影响更大,尤其是信道间隔较小的情况下,非恒包络调制信号的误码性能恶化严重.该研究为数字通信系统的工程设计提供了一种可借鉴分析方法. 相似文献
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VHF跳频通信系统功率放大器的研制 总被引:1,自引:0,他引:1
设计了一种用于跳频通信系统的射频功率放大器.该放大器具有较高的线性度,同时又能实现高功率的稳定输出,低功率输出大于0.25 W,中功率输出大于4.5 W,滤波器衰减损耗小于2 dB,谐波抑制大于48 dB.介绍了VHF跳频发射机系统,包括逻辑电平转换单元、调制环单元、射频环单元、频率合成器单元和功放单元;着重对射频功率放大器的性能进行了分析,指出了提高功放线性度的特殊方法;给出了射频功率放大器的硬件电路设计过程.最后,对射频功率放大器进行测试,结果表明,其性能指标完全达到系统设计要求,并有所提高,而且具有较强的实用性. 相似文献
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Recruitment characteristics of nerve cuff electrodes implanted in four cats for five months were measured. Monopolar, bipolar, and tripolar configurations were considered. Approximately twice the current was required to achieve a given response using the tripolar configuration as compared with monopolar stimulation. Bipolar stimulation also required more current than monopolar stimulation. Using the recruitment data, a number of strategies for modulating muscle tension were considered. It was shown that both pulse amplitude and pulse duration should be software-selectable to achieve adequate control of muscle tension when using either pulse amplitude modulation or pulse duration modulation. When using pulse amplitude modulation, it was found to be desirable to operate at a low pulse duration in the high end of the allowable range for pulse amplitude. For pulse duration modulation, one should operate at a low pulse amplitude in the high end of the allowable range for pulse duration. The effect of pulse amplitude and pulse duration step size on the maximum step change in muscle tension and the linearity of the recruitment curves were examined. The use of logarithmic steps in the modulation parameter was examined and was shown to result in improved controllability and linearity. 相似文献
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双环推挽型高线性M-Z光强调制器特性研究 总被引:2,自引:0,他引:2
对损耗影响下的双环推挽(TRAPP)型马赫一曾德(M-Z)光调制器的线性特性进行了研究。分析表明,存在损耗时,设计特定的光微环与M-Z干涉臂间的耦合大小,并控制偏置点,总可以获得2次与3次高阶项为零的调制曲线;当微环1周损耗小于5dB时,线性范围总是可以达到90%以上;当损耗过大时,导致基于微环的全通滤波器的相位响应受限,虽然调制曲线在自身范围内依然保持高的线性度,但调制曲线固有的调制深度将限制整体线性范围。 相似文献
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Berceli T. Frigyes I. Gottwald P. Herczfeld P.R. Mernyei F. 《Microwave Theory and Techniques》1992,40(5):910-915
When the number of TV channels is high, a significant harmonic and intermodulation distortion arises. These distortions can be reduced by improving the modulation linearity of the laser or by applying a more appropriate modulation method. Both solutions are discussed and evaluated in detail. The linearity has been significantly improved by applying an active matching technique. The improvement achieved by the new driving circuit over the conventional one is 15 dB considering the third harmonic distortion. The sensitivity of QPSK TV transmission to disturbing interferences has been investigated. A so-called group modulation method offers a better approach for optical multicarrier TV transmission 相似文献
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L. Yang A. Asenov J. R. Watling M. Borii J. R. Barker S. Roy K. Elgaid I. Thayne T. Hackbarth 《Microelectronics Reliability》2004,44(7):1101-1107
Based on careful calibration in respect of 70 nm n-type strained Si channel Si/SiGe modulation doped FETs (MODFETs) fabricated by Daimler Chrysler, numerical simulations have been used to study the impact of the device geometry and various doping strategies on device performance and linearity. Both the lateral and vertical layer structures are crucial to achieve high RF performance or high linearity. The simulations suggest that gate length scaling helps to achieve higher RF performance, but degrades the linearity. Doped channel devices are found to be promising for high linearity applications. Trade-off design strategies are required for reconciling the demands of high device performance and high linearity simultaneously. 相似文献
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This paper presents a transmitter IC with BPSK modulation for an ultra-wide band system.It is based on up-conversion with a high linearity passive mixer.Unlike the traditional BPSK modulation scheme,the local oscillator (LO) is modulated by the baseband data instead of the pulse.The chip is designed and fabricated by standard 0.18μm CMOS technology.The transmitter achieves a high data rate up to 400 Mbps.The amplitude of the pulse can be adjusted by the amplitude of the LO and the bias current of the dri... 相似文献
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P.-L. Liu B.J. Li Y.S. Trisno 《Photonics Technology Letters, IEEE》1991,3(2):144-146
An electrooptic modulator which offers high linearity and low intermodulation distortion (IMD) is proposed. The modulation characteristics, harmonic and intermodulation distortions, are calculated. In the two-tone test with an optical modulation depth of 16% for each channel, the third-order IMD is expected to be as low as -95 dB. Such a linearized electrooptic modulator used in conjunction with diode-pumped solid-state lasers can be expected to outperform directly modulated injection lasers for CATV transmission systems.<> 相似文献
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第3代移动通信系统采用了线性化调制方式,对放大器的线性度的要求也很高,因此设计一款高线性度的放大器有着十分重要的意义。针对前馈射频放大器设计中插入导频法自适应控制而采取的一种解决方法:通过RF2422正交调制双音频信号的载波信号作为导频信号,利用音频信号幅度的变化来控制幅度与相位变化,并利用ADS做出部分仿真。 相似文献
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We demonstrated a linearized Y-fed directional coupler modulator in Z-cut LiNbO/sub 3/. The proof-of-concept device employed two electrode sections of opposite polarity whose lengths were chosen based on the results of our previous theoretical modeling. A highly linear modulation characteristic and improved tolerance to fabrication errors were achieved with a simple design, in excellent agreement with the theory. The linearity exceeded 90% over a wavelength range of 45 nm, centered around 1530 nm, with a maximum linearity of 97% at 1510 nm and a maximum modulation depth of 98%. By comparison, the linearity of conventional modulators is typically around 70%. Thus the device was proven to have a high linearity with a wide usable spectral range and relaxed fabrication tolerances. 相似文献
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电光强度调制一般是基于线性理论,在某些高精密系统中,其非线性误差分析对于系统的指标评定和误差校正具有一定意义。首先,详细推导了电光强度调制器在一般情况下的光强调制函数,并阐述了工作点的重要性;接着,对标准工作点及其附近的情况进行了非线性误差的计算分析,且分别给出了表达式;然后,从频域的角度讨论高次谐波对调制的影响;最后,在时域上比较不同调制深度下的实际调制和理想调制效果。公式推演和实验分析表明,工作点的高度稳定性和小信号调制可以减小非线性误差,这些误差可以定性定量地表示出来,有望通过补偿的方法提高电光强度调制系统的精度。 相似文献