共查询到20条相似文献,搜索用时 109 毫秒
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在电容传声器,包括驻极体传声器中,由于传声器头的内阻抗非常高,一般都紧接传声器头加装一前置放大器,用以变换阻抗。然而,前置放大器输出的固有电噪声又限制着传声器的动态范围向低端发展,即传声器所能接受声信号的最低声压级受到传声器等效噪声级的限制。因此,测量和降低前置放大器以至整个传声器的固有电噪声,已经成为保证和提高传声器性能的一个重要问题。根据定义,在测量固有电噪声时,必须加上 A 计权,以模拟人耳的听 相似文献
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文章介绍了无线传声器用和小型语言扩声用的二种驻极体电容传声器的设计,从理论和实验上分析了无方向性和单方向性传声器频响、灵敏度、指向性的有关因素。 相似文献
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利用4143型互易校准仪校准Φ12.7mm标准电容传声器自由场灵敏度的设想陕西省物理研究所蒋渭鑫一、引言用三传声器法时,因为计算灵敏度的公式中有三个电转移阻抗,因而在计算测量总准确度时,应计及三个电转移阻抗的准确度。而辅助声源法的公式中只有一个电转移... 相似文献
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测试电容传声器的设计国营797厂庄国胜一、引言测试电容传声器(也称测量传声器)作为声学测量的基准,主要用于声压和频率的测量。从换能原理上来说,它是一种压强式电容传声器。从使用上来说,测试电容传声器具有良好的时间和环境的稳定性,宽广平坦的频率特性,灵敏... 相似文献
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A preamplifier design is presented which is based on a common-drain JFET input. The midband noise performance is En = 0.42 nV/Hz?, In = 2.8 fA/Hz?. The circuit has considerably less input capacitance than comparably noisy common-source amplifiers. It is particularly useful for preamplification of 0.1 to 10 MHz signals from liquid-helium-cooled radiation detectors. 相似文献
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静电激励放大器是电容传声器的性能测量、分析及生产过程中的检验不可缺少的设备。这里简要介绍一种这样设备的设计方案及电路设计,并进行了电路分析。 相似文献
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《Microelectronics Journal》2002,33(1-2):21-28
We present and compare the different designs of micromachined silicon condenser microphones. The aim is to develop the microphones with high sensitivity and low fabrication cost. Slotted and corrugated diaphragms have been designed and fabricated in order to increase the mechanical sensitivity of microphones. At the same time, we developed the fabrication process for the low stress or stress-free multilayers polysilicon used as the microphone diaphragms. To increase the microphone chip density on one wafer and avoid the sticking problem during the wet release process, a new process design using deep reactive ion etching is proposed, which is available in our laboratory. 相似文献
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Z. Hamaizia N. Sengouga M. Missous M.C.E. Yagoub 《Materials Science in Semiconductor Processing》2011,14(2):89-93
In this work, the design of a novel low-noise amplifier (LNA) based on 1 μm gate-length InGaAs/InAlAs/InP pHEMT transistors is discussed. Designed for radioastronomy applications, this amplifier exploits a common-drain configuration as input stage and a common-source inductive degeneration topology as output stage. It exhibits a maximum gain of 30 dB within an input 1 dB compression point of −16 dBm. The noise figure is 0.4 dB with an input return loss greater than −10 dB and an output return loss of −12.5 dB. The LNA consumes 85 mW from a 1.5 V power supply. 相似文献
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驻极体电容传声器(简称话筒)其专用结型场效应( JFET)与正向箝位二极管D1组成简单组合器件,称之为传声器管.该产品由P+N结栅控制沟道电流,不同于MOST的绝缘栅结构.因此在设计中并没有静电放电(ESD)防护装置.并且执行的标准截然不同,随着传声器管的应用逐渐扩大,要求提高电性能;为了抗射频(RF)噪声干扰在传声器... 相似文献
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对现有的基于自动波束形成的传声器阵列语音信号增强算法提出了改进,将各传声器采集到的信号利用ABF(自适应波束形成)进行延时补偿并求和,消除信号中弱相干和不相干噪声;再利用特征空间逼近的方法进一步去除残留的噪声。将一种定阶方法应用到基于特征空间分解的语音信号增强中,利用其“最大稳定”原理,使得有效信号模型的阶数尽可能不受原始信号信噪比的影响,消除了传统定阶过程中的随意性和不稳定性。仿真结果表明:把自适应波束形成技术和特征空间逼近的方法结合起来,能够取得良好的去噪效果。 相似文献
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Taejin Lee Daeyoung Jang Kyeongok Kang Jinwoong Kim Dae‐Gwon Jeong Hareo Hamada 《ETRI Journal》2005,27(2):153-165
The main purpose of a spatial audio system is to give a listener the same impression as if he/she were present in a recorded environment. A dummy head microphone is generally used for such purposes. Because of its human‐like shape, we can obtain good spatial sound images. However, its shape is a restriction on its public use and it is difficult to convert a 2‐channel recording into multi‐channel signals for an efficient rendering over a multi‐speaker arrangement. In order to solve the problems mentioned above, a spatial audio system is proposed that uses multiple microphones on a rigid sphere. The system has five microphones placed on special points of the rigid sphere, and it generates audio signals for headphone, stereo, stereo dipole, 4‐channel, and 5‐channel reproduction environments. Subjective localization experiments show that front/back confusion, which is a common limitation of spatial audio systems using the dummy head microphone, can be reduced dramatically in 4‐channel and 5‐channel reproduction environments and can be reduced slightly in a headphone reproduction 相似文献
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