共查询到15条相似文献,搜索用时 187 毫秒
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为提高脉冲激光3D成像系统中提取目标距离和强度信息的精度,对时刻鉴别和峰值保持电路进行了深入研究。在简要分析激光测距体制及探测器选择的基础上,给出了激光3D成像系统结构框图:激光器输出信号经半反半透棱镜,反射光线触发参考APD作为计时起始信号,以提高计时基准。给出了恒定阈值鉴别与恒比定时鉴别相结合的时刻鉴别电路,在提高时刻鉴别精度的同时可有效消除噪声对电路的影响。峰值保持选取基于OPA861的跨导型峰值保持电路。在实验室搭建了回波信号模拟系统,并在此基础上对电路性能进行测试。最后,给出了实验结果。结果显示:时刻鉴别电路精度优于1 ns;当输入窄脉冲峰值信号低于800 mV时,峰值保持电路保持精度优于2.63%。整个结果满足后续实验要求。 相似文献
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针对跟踪激光雷达对回波信号峰值幅度的需求,分别采用电压型及跨导型峰值保持电路实现窄脉冲信号峰值保持,并测试了不同跨导放大器的保持效果,最终解决了激光雷达回波信号峰值保持的快速以及幅度问题。实验结果表明:采用跨导型峰值保持电路,同时利用双倍缓冲保持方法扩大保持电压峰值范围,可以实现回波信号的峰值提取。该方法采用跨导放大器实现对窄脉冲信号峰值保持的快速性,并利用双倍缓冲器提高驱动能力以及最大可保持峰值。对上升沿约为6ns的脉冲信号,可保持峰值最高达到2.5V、响应时间小于2ns。 相似文献
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针对激光扫描仪接收系统对信号窄脉宽、高重频、大带宽的设计要求,提出2种保持时间可调的峰值保持电路的设计方法。一种利用跨导型放大电路实现峰值保持,单稳态触发器实现保持时间控制;一种利用FastFET运算放大器和与门延时实现保持时间可控的峰值保持电路。通过软件仿真对2种设计方法进行对比分析,选择更适合激光扫描仪接收系统的跨导型峰值保持电路。经实验验证,该电路可对15 ns脉宽、200 kHz重频和50 MHz带宽的信号有效保持,且保持时间可调。 相似文献
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对电路进行行为级模拟的关键是建立电子子模块的行为模型,用以描述电路模块的功能以及电路非理想效应的影响。本文采用瞬态分析方法,建立了基本模拟单元电路开关电容积分 的行为模型。由于对积分器中的运算放大器采用了单极点跨导运放模型,考虑了其有限增益、带宽、转换速率和输出阻抗的影响,提高了开关电容积分器行为模型的精度。电路模拟的结果表明,模型的误差在3%以内。 相似文献
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Qiuting Huang Basedau P. 《Very Large Scale Integration (VLSI) Systems, IEEE Transactions on》1997,5(4):408-416
The current consumption of crystal oscillators is usually determined by the steady-state amplitude requirement, rather than the minimum transconductance for oscillation to exist, In a bipolar implementation transconductance is proportional to current, so that current consumption scales with frequency and load capacitance in the same way as transconductance. In a complementary metal-oxide-semiconductor (CMOS) implementation, current scales as the square of transconductance. It is therefore important to distinguish current from transconductance in power estimation for high frequency oscillators. Analytical expressions relating current to steady-state amplitude are used in this paper to estimate the minimum power required for a crystal oscillator at a given frequency. A 78 MHz crystal oscillator is described, which forms part of a regulated system in a pager where the oscillation frequency is controlled digitally to sub-ppm accuracy. The oscillator can be pulled from ±65 ppm to the required frequency with 0.2 ppm accuracy, with a maximum current consumption of 197 μA. The circuit has been fabricated in a 1-μm CMOS technology. The measured phase noise is -113 dBc/Hz at 300 Hz offset 相似文献
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改进了一种精确恒定跨导偏置电路,通过对电流和晶体管尺寸的设计使主电路跨导恒等于外接高精度电阻跨导,与传统结构相比具有更高的精度.将该偏置电路应用于无线传感网芯片中9阶Gm-C椭圆低通滤波器的设计,使该滤波器省去了片上调谐电路的设计,在降低功耗的同时提高了精度,节省了面积.设计基于SMIC 0.18μm 1.8 V 1P6M CMOS工艺,芯片面积仅为0.9 mm×0.22 mm,测试结果表明,该滤波器的截止频率与设计值相差在1%以内,输入噪声电压小于25 nV/√Hz,消耗电流仅为0.9 mA,满足无线传感网节,点芯片的要求. 相似文献
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A capacitance multiplier circuit, using operational transconductance amplifiers, is realised. The circuit provides widerange linear control of the capacitance value with direct voltage or current. This makes the realisation of large-valued grounded capacitors possible in IC fabrication. The linearly tunable capacitor is expected to find attractive applications in voltage/current-controlled filters, oscillators etc. 相似文献
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Takao Tsukutani Masami Higashimura Yasuaki Sumi Yutaka Fukui 《International Journal of Electronics》2013,100(12):1435-1442
This paper presents a realization of a voltage-mode active-only biquadratic circuit. The proposed circuit is constructed employing solely operational amplifiers and operational transconductance amplifiers (OTAs). The circuit configuration is obtained from a second-order structure with two integrator loops. The circuit can realize low-pass, band-pass, high-pass, band-stop, low-pass notch, high-pass notch and all-pass transfer functions by suitably choosing the input and output terminals, and the circuit characteristics can be electronically tuned through adjusting the transconductance gains of OTAs. Some examples are given together with simulated results by PSPICE. The circuit configuration is very suitable for implementation in both bipolar or CMOS technologies. 相似文献