共查询到20条相似文献，搜索用时 15 毫秒
1.
In this article, a modified microstrip Wilkinson power divider with harmonics suppression for GSM communications applications is presented. For low‐pass filter designing, one open stub, one radial resonator, and two rectangular resonators are used. According to results related to insertion losses (|S21| and |S31|), stopband is wide and equal to 7.5 GHz (3.4‐10.9 GHz), under the condition of 20 dB harmonic suppression level. The results show that at the designed frequency of 1.8 GHz, the input return loss (|S11|) and output return losses (|S22| and |S33|) are better than 22 dB, and the isolation between of output ports (|S32|) is better than 30 dB. The size of the proposed power divider is compact and equal to 10.6 × 14.6 mm2. Finally, the proposed power divider was fabricated and the measurement results illustrate a good agreement with simulation results. 相似文献
2.
A new circuit topology using a current‐mode low‐pass filter for sinusoids has been presented. The technique is relatively simple, in the proposed circuit, only three identical current‐mode low‐pass filters are connected to each other to realize the small signal path. No external passive components are required except for three capacitors. When compared with LC oscillators, the die area of this work, without inductors, is much smaller. When compared with voltage‐mode ring oscillators, the supply voltage of this work is much lower. As a particular example, a 2.4 GHz, 1.2‐V power supply, 5‐mW sinusoidal oscillator is demonstrated. The oscillation frequency is tuned by the value of that three capacitors, over ～900 MHz, and the tuning range is 37.5%. The phase noise results in ?94 and ?120 dBc/Hz at 1 and 10 MHz from the carrier, respectively. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010. 相似文献
3.
An elliptical function low‐pass filter (LPF) with ultra wide stopband and sharp cutoff frequency is proposed. This filter is composed of symmetrical cascaded modified hairpin resonators and U‐shaped resonators. The transition band is from 1 to 1.21 GHz with ?3 and ?20 dB, respectively. For this filter, the return loss is better than 17 dB in 80% of passband width, where the insertion loss is less than 0.3 dB. The band‐stop rejection is greater than 20 dB from 1.21 to 26.35 GHz and 40 dB from 1.35 to 12.5 GHz. To validate the design and analysis, the proposed LPF has been designed and fabricated on a 20 mil thick RO4003 substrate with a relative dielectric constant 3.38 and loss tangent of 0.0021. The filter is evaluated by experiment and simulation with a good agreement. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:314–321, 2014. 相似文献
4.
We propose a measurement feedback controller for a class of feedforward nonlinear systems under sensor noise. The sensor noise has unknown magnitude, frequency, and phase. Our proposed controller is coupled with a low‐pass filter in such a way that the sensor noise is attenuated. We show that the controlled system results in bounded states whose ultimate bounds are inversely proportional to the minimum frequency of the sensor noise. Our result is further generalized to work in a case where the sensor noise is only required to have a Fourier transform with finite energy. Moreover, if the sensor noise enters only at partial states, depending on the location of the sensor noise, the ultimate bounds of the particular states can be made arbitrarily small via the gain factor of the controller. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
5.
Tong
Ma 《国际强度与非线性控制杂志
》2020,30(11):4397-4417
》2020,30(11):4397-4417
In this article, an extended filtering high‐gain output feedback controller is developed for a class of uncertain nonlinear systems subject to external disturbances. The nonlinearities under consideration satisfy a semiglobal Lipschitz condition. The proposed control architecture integrates the extended state observer (ESO), high gain, and low‐pass filter together. None of them is used alone. The ESO can not only estimate the unknown internal state, but also deliver a good property of disturbance rejection simultaneously due to the presence of high gain. Since the high gain deteriorates the robustness of the system, a low‐pass filtering mechanism is added in the control law to filter away aggressive signals and recover the robustness. The filtering control law is designed to compensate the nonlinear uncertainties and deliver a good tracking performance with guaranteed stability. The matched uncertainties are canceled directly by adopting their opposite in the control signal, whereas a dynamic inversion of the system is required to eliminate the effect of the mismatched uncertainties on the output. Since the virtual reference system defines the best performance that can be achieved by the closed‐loop system, the uniform performance bounds are derived for the states and control signals via comparison. Numerical examples are provided to illustrate the effectiveness of the novel design via comparisons with the model reference adaptive control method and L1 adaptive controller. 相似文献
6.
Class G power amplifier (PA) design guidelines are presented and experimentally validated, showing the interesting features of the new approach. For the same operating conditions, the Class G amplifier exhibits superior performances if compared to a tuned load one in large signal gain, output power, and third‐order intermodulation (IM3), with a power‐added efficiency (PAE) improvement of 38.5%. © 2000 John Wiley & Sons, Inc. Int J RF and Microwave CAE 10: 366–378, 2000. 相似文献
7.
Navid Arbabi Mohammad Almalkawi Vijay Devabhaktuni Mustapha Yagoub Arjuna Madanayake 《国际射频与微波计算机辅助工程杂志》2012,22(2):147-152
A compact realization of composite low‐pass filter is presented in this article. The filter is realized using on‐chip spiral inductors and metal–insulator–metal capacitors and features an attenuation pole near the cutoff frequency leading to a sharper attenuation response. As well, it offers good matching properties in the passband. Space‐mapping‐based algorithm is used in the design/optimization of spiral inductors toward achieving high quality factors at the filter cutoff frequency. The realization of the proposed filter is compact in size, suitable for monolithic microwave integrated circuit applications, and exhibit broad upper stopband frequency characteristics. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2012. 相似文献
8.
为了降低H264中I帧编码模式选择时的计算量,提出了一种快速编码算法。该方法首先选择适当的滤波算子对待编码宏块进行平滑滤波,同时使用滤波后的结果与原始宏块数据进行比较来得到滤波残差量;然后将该滤波残差量作为依据,提前判断出当前宏块编码所属的基本模式集,这样由于减小了候选模式的范围,因而提高了模式决定的效率。在判定过程中还使用了双阈值方法,该方法可确保在作出合理判决时,亦不影响图像质量。采用该算法不仅一定程度上降低了计算复杂度,并且对图像质量的影响可以忽略不计。实验表明,这种新的算法可以降低约16%的计算量,而编码图像峰值信噪比的下降只有01dB,且对比特率的影响不到1%。 相似文献
9.
本文详细介绍了低通滤波器的数学模型及其滤波的仿真效果,而后介绍了对其进行数字化的过程,并给出了这种数字滤波器的PLC程序,最后介绍了这种数字滤波器在低压铸造温度采样中的应用。应用实践表明,这种数字滤波的效果是相当好的。 相似文献
10.
Multiharmonic manipulation is presented as the most effective solution to improve power amplifier (PA) efficiency performances. Remarkable improvements in output power, power gain and power‐added efficiency (PAE) are demonstrated, properly manipulating the input and output second and third harmonics, as compared to more classical design approaches. Experimental results at 5GHz confirm the feasibility, the validity and effectiveness of the proposed approach, increasing the maximum measured power‐added efficiency from 39% to 61% © 2001 John Wiley & Sons, Inc. Int J RF and Microwave CAE 11: 366–384, 2001 相似文献
11.
设计一个具有斜8字型伏安特性的忆阻器模拟电路模型,并将此模型应用于构建低通滤波电路。进行Multisim仿真并制作了相应的实物电路,仿真和实验结果表明该电路模型可以正确模拟忆阻器的特性,由其构建的忆阻低通滤波电路具有时变特性。 相似文献
12.
本文提出一种基于变学习率三角基函数神经网络的线性相位4型FIR滤波器设计方法。该方法根据三角基函数神经网络与线性相位4型FIR滤波器幅频特性之间的关系,构建了一种变学习率三角基函数神经网络模型,在神经网络训练过程中引入变学习率算法自调整学习率取值,解决学习率通常依靠经验或试凑法确定带来的不确定性,提高神经网络的学习效率和收敛速度。通过训练神经网络的权值,使设计的FIR滤波器幅频响应与理想幅频响应在整个通带和阻带内的误差平方和最小。文中利用该方法对FIR高通滤波器和带通滤波器进行了优化设计,仿真结果表明了该方法设计FIR滤波器的有效性和优越性。 相似文献
13.
A millimeter‐wave ultrawideband two‐way switch filter module is presented in this article. The switch filter module covers whole Ka‐band (26–40 GHz), and is composed of two wideband band‐pass filters and two monolithic microwave integrated circuit (MMIC) single pole two throw (SP2T) switches. One filter is realized using E‐plane iris waveguide band‐pass filter, and another is realized by a novel 11‐pole three‐line microstrip structure band‐pass filter. Compared with the traditional three‐line filter, the proposed three‐line filter not only retains virtues of the traditional three‐line filter, but also resolves drawbacks of it, which include discontinuities between adjacent sections, many parameters of design, and no effective matching circuits at input/output ports. The developed switch filter module is fabricated using hybrid integrated technology, which has a size of 51 × 26 × 9.8 mm3, and interconnections between MMICs and microstrip are established by bond wires. The fabricated switch filter module exhibits excellent performances: for two different states, the measured insertion loss and return loss are all better than 7 and 10 dB in each pass‐band, respectively. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:305–310, 2015. 相似文献
14.
In this letter, a compact microstrip lowpass filter (LPF) is designed using serial connecting of two modified asymmetric hairpin resonators. The proposed design is consists of four open‐circuited stubs that are used to suppress spurious harmonics in the stopband. The proposed filter has wide‐stop band with attenuation level better than ?28 dB from 2.16 up to 26.1 GHz and sharp roll‐off. The proposed LPF has ?3 dB cutoff frequency equal to 2.11 GHz, wide stopband width around 12th harmonic suppression and insertion loss less than 0.1 dB at about 85% of the passband. The excellent agreement is observed between the simulated results and measured values of the fabricated LPF. 相似文献
15.
一种低压低功耗的亚阈型CMOS基准电压源 总被引：1，自引：0，他引：1
介绍一种低压、低功耗和低温度系数CMOS基准电压源,该基准电压源的核心MOSFET工作在亚阈值区,采用亚阈值型MOSFET低于某个特定偏置点时,具有负温度系数的特点.电路用标准的0.35 μm CMOS工艺设计,在-40℃～+110℃范围的温度系数为262.6 ppm/ ℃时,基准的输出电压为345.36 mV.本文也... 相似文献
16.
A coupled‐line band‐pass filter (BPF) with T‐shaped stub structure is presented. Five transmission poles within the passband and eight deep transmission zeros (TZs) from 0 to 2f0 (f0 denotes filter's center frequency) are realized through input impedance calculations. With the simple T‐shaped structure, the positions of six TZs can be appropriately adjusted to achieve high frequency selectivity and stopband rejection. For demonstration, a BPF prototype centered at 2.05 GHz is designed and fabricated, whose measured rejection levels are of over 45.5 dB at lower stopband and better than 19.5 dB at upper stopband. The simulation and measurement results are in good agreement, which validates the design idea. 相似文献
17.
Kenneth V. Puglia 《国际射频与微波计算机辅助工程杂志》2003,13(6):447-458
A compact, band‐pass filter utilizing multi‐element resonators, structured from sections of distributed transmission lines, is presented. A band‐pass filter design procedure is established that emphasizes CAD techniques to characterize the individual resonators and to determine the resonator coupling values required for a specified pass‐band response. Detailed band‐pass filter design examples are illustrated and simulation results are employed to validate the design procedure. © 2003 Wiley Periodicals, Inc. Int J RF and Microwave CAE 13, 447–458, 2003. 相似文献
18.
设计基于FPGA和旋转变压器的无刷直流电机转子位置及转速测量电路,利用FB9412PB将旋转变压器输出的正余弦模拟信号转换为角度和速度数字信号,并以并行口的方式输出,存储在FPGA内部RAM中,通过数字低通滤波算法处理后实时输出给电机控制器.该电路现已成功应用于某电动舵机控制系统中,具有简便、实用、可靠的特点. 相似文献
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20.
随着智能电网的提出和推广,基于电力线载波的通信系统因成本低、通信速率高等优点得到了广泛使用.然而电力线载波通信存在频率选择性衰落、多径衰落以及脉冲干扰等不利条件,为了给智能电网提供高速可靠的通信手段,设计了基于正交频分复用的高速电力线载波通信系统,采用粗步捕获+精准同步的两次同步技术.为了消除大动态噪声和干扰对同步绝对门限设定的影响,提出一种窗口滑动方法,在等分窗口内用后一部分的能量与前一部分的能量的比值作为判决变量,消除大动态噪声和干扰的影响.仿真结果表明,在电力线载波环境下,设计的方案能够很好地解决频率选择性问题,同时具有显著的抗脉冲干扰和多径衰落能力. 相似文献