红外焦平面器件的信息获取电路技术

红外焦平面阵列器件是现代红外成像系统的关键器件,它包括红外探测器阵列和读出电路两部分。其信号获取电路是处理焦平面输出信号的部分,主要指与读出电路接口的放大电路。本文主要综合了红外焦平面器件的信息获取电路及其相关技术,并就其中的关键技术进行简要分析。     

红外焦平面器件读出电路技术

本文是一篇关于红外焦平面阵列器件的综述性文章。主要介绍了红外焦平面阵列器件的分类、定义、应用、组成部分、发展趋势,其中重点对红外焦平面器件读出电路技术作了详尽的论述。     

红外焦平面阵列CMOS读出电路参数的计算机辅助测试系统

读出电路是红外焦平面器件研究的关键技术之一,本文研制出一种用于CMOS读出电路参数测试的计算机辅助测试系统。该系统可靠、精度高,有完整的软硬件环境,以适应各种读出电路的测试。     

红外焦平面器件的研制与展望

从焦平面器件研制的角度出发，分析了焦平面技术的现状和发展趋势，认为红外焦平面的难点在于大规模，高均匀性，高性能的红外探测器阵列的制造，同时强调了材料，杜瓦瓶，致冷器，读出电路等关键技术在加速焦平面器件研制中所起的重要作用。     

光谱成像用红外焦平面读出电路研究

红外焦平面是光谱成像系统的核心器件。讨论了多光谱用红外焦平面读出电路的特点,设计了用于多光谱成像的64×16元红外焦平面读出电路。读出电路采用CTIA输入级,快照式曝光方式,边积分边读出工作。电路芯片与InGaAs光敏芯片阵列通过铟柱倒焊的方法,组成混成互连焦平面器件,像元间距50μm,响应波段0.9～1.7μm,盲元率0.2%,半阱时的响应不均匀性4.7%。     

红外焦平面读出电路技术及发展趋势

从红外焦平面技术的发展背景出发,论述了读出电路在红外焦平面信号传输中的作用并介绍其基本框图,讨论了CCD读出电路和CMOS读出电路各自的特点,并分析了国内外红外焦平面读出电路的现状,最后提出了红外焦平面阵列读出电路今后的研究方向.     

基于虚拟仪器的IRFPA RPIC参数测试系统

读出电路是红外焦平面器件研究的关键之一，作者研制出一种基于虚拟食品的读出电路参数测试系统。该系统运行稳定、可靠、测试精度高，有完整的软硬件环境，可以测试各种读出电路。     

微测辐射热计阵列读出电路的单片集成设计

微测辐射热计阵列读出电路的单芯片集成,有利于红外焦平面阵列的智能化和红外成像系统的便携化发展.提出了一种非致冷红外焦平面阵列读出电路,基于SMIC 0.18 μmCMOS工艺,采用CTIA型单元读出电路结构,实现了偏置模块、驱动信号源模块、电流积分模块、相关双采样模块(CDS)和缓冲输出模块的单芯片集成,成功制造了1×8读出电路原型.仿真结果表明,设计的读出电路的线性度大于99％,功耗小于5 mW,适合于大面阵移植.     

红外焦平面失效现象仿真研究

在性能较差的红外焦平面器件中,其背景图像经常出现一些现象,比如"黑线"、"锯齿"、"滴落圆"等,其原因可能是红外焦平面器件有缺陷或其读出电路存在问题.本文针对红外焦平面可能出现的各种缺陷,将其等效为失效性模型,用EDA软件分别对采用DI和CTIA两种读出结构的红外焦平面进行失效性等效模拟分析.通过对3×3和10×10规模的红外焦平面输出信号进行模拟,分析了背景图像中失效现象产生的原因.红外焦平面失效现象模拟分析得出的结果,为红外焦平面读出电路结构的改进提供了参考依据.     

红外焦平面阵列读出电路技术分析

从红外焦平面技术的发展背景出发,论述了读出电路在红外焦平面信号传输中的作用;讨论了用于实现红外焦平面阵列读出电路的一些实施技术;并对各种实现技术进行了分析比较;最后提出了红外焦平面阵列读出电路今后的研究方向。     

Terahertz Sensor Using Photonic Crystal Cavity and Resonant Tunneling Diodes

In this paper, we report on a terahertz (THz) sensing system. Compared to previously reported systems, it has increased system sensitivity and reduced size. Both are achieved by using a photonic crystal (PC) cavity as a resonator and compact resonant tunneling diodes (RTDs) as signal source and as detector. The measured quality factor of the PC cavity is higher than 10,000, and its resonant frequency is 318 GHz. To demonstrate the operation of the refractive index sensing system, dielectric tapes of various thicknesses are attached to the PC cavity and the change in the resonator’s refractive index is measured. The figure of merit of refractive index sensing using the developed system is one order higher than that of previous studies, which used metallic metamaterial resonators. The frequency of the RTD-based source can be swept from 316 to 321 GHz by varying the RTD direct current voltage. This effect is used to realize a compact frequency tunable signal source. Measurements using a commercial signal source and detector are carried out to verify the accuracy of the data obtained using RTDs as a signal source and as a detector.     

Maximum Likelihood Stacking in White Gaussian Noise with Unknown Variances

In seismic exploration, the process of estimating the source produced signal common to a collection of sampled data recordings contaminated with additive noise is known as stacking. Stacking is used when a low energy acoustic source can be repeated in the same physical location (or nearly so) and a collection of data recordings are gathered at the same electromechanical transducer from the multiple source initiations. This stacking process is primarily aimed at reducing environmental noise which frequently dominates each individual recording when low energy sources are used. This is in contrast to other techniques used to reduce or eliminate so called source generated noise which behaves as signal in the stacking process. Specifically, the problem we address is the simultaneous maximum likelihood (ML) estimation of signal values and unknown noise distribution parameters from a collection of sampled data recordings, each containing the same signal sequence. In this paper we restrict our consideration to independent, zero mean, Gaussian noise variates with unknown variance which may differ between data records. This model is justified when a broadband analog noise source is subsequently low pass filtered along with the signal and the result sampled at the Nyquist rate. The linear filtering tends to produce a Gaussian noise process and the Nyquist rate sampling produces approximately uncorrelated samples. The ML estimates of signal values and noise variances are obtained numerically by steepest ascent.     

Local Linear Estimators for the Bioelectromagnetic Inverse Problem

Linear estimators have been used widely in the bioelectromagnetic inverse problem, but their properties and relationships have not been fully characterized. Here, we show that the most widely used linear estimators may be characterized by a choice of norms on signal space and on source space. These norms depend, in part, on assumptions about the signal space and source space covariances. We demonstrate that two estimator classes (standardized and weight vector normalized) yield unbiased estimators of source location for simple source models (including only the noise-free case) but biased estimators of source magnitude. In the presence of instrumental (white) noise, we show that the nonadaptive standardized estimator is a biased estimator of source location, while the adaptive weight vector normalized estimator remains unbiased. A third class (distortionless) is an unbiased estimator of source magnitude but a biased estimator of source location.     

基于直接数字频率合成的可编程遥测信号源

针对传统的遥测信号源缺乏灵活可配置性、通用性差的问题,提出采用FPGA和DDS技术为核心设计灵活可配置的可编程遥测信号源。该信号源的硬件电路主要由低成本FPGA芯片和DDS芯片组成,采用Verilog语言进行编程,使FPGA控制核心输出不同的相位、频率、波形等控制字信息给DDS芯片,经DDS芯片后输出所需波形。仿真表明,该信号源能够输出频率范围在0～12.5MHz的频率、相位可调的正弦波、三角波、方波等波形信号,具有一定的通用性。     

基于DSP的数字信号源软件设计

介绍使用ADSP21160高速数字信号处理(DSP)芯片,实现数字信号源的程序设计;分析使用DSP实现数字信号源的可行性,介绍仪器设备中常用的部分信号形式,列出CW,LFM信号的数学公式,给出工程文件的建立和程序设计流程图,以及在实际应用中注意事项,利用ADSP21160的Simulator仿真软件的plot画图功能,画出程序运行产生的部分波形,说明使用DSP设计数字信号源是完全可行的,比模拟信号源有明显的优越性,修改方便、使用灵活,根据不同的算法就可以产生不同的信号。该文应用ADSP21160数字信号处理器软件实现了CW,LFM信号在不同包络中形成的复杂窄脉冲和多脉冲数字信号源。     

一种新的多通道混合语音时域盲分离算法

卷积混合语音进行盲源分离时,不能直接应用独立分量分析（ICA）算法。采用一种新的卷积混合语音模型,对多通道混合语音使用近来提出的时域EFICA算法进行盲分离,然后利用聚类和重构算法来恢复源信号。通过真实语音实验表明,提出的算法能有效地分离混合语音信号。     

基于信源数目估计的超定盲信号分离

针对盲信号分离中信道噪声大、信号分离效果差等问题,在传统主分量分析和特征值分解方法的基础上,提出了一种基于信源数目估计的超定盲信号分离方法。首先,采用主分量分析和最大似然估计方法分别对混合矩阵和噪声协方差进行估计,用于对信道噪声的估计与去除;然后,采用交叉验证法对源信号维数进行估计,实现盲信号分离。为了验证提出算法的分离效果,对轻拖尾与轻拖尾混合信号以及重拖尾与轻拖尾信号混合情况进行仿真实验验证,结果表明该算法具有良好的分离效果。     

基于智能单粒子与信号变化度的盲源分离算法

提出了一种新的基于智能单粒子优化的有序盲源分离算法。采用信号变化度作为分离的目标函数,利用球坐标变换方法对分离向量进行变换,使用智能单粒子优化算法对目标函数进行求解,通过去相关方法从混合信号中去除已分离出的源信号成分,最终实现按照信号变化度降序分离出各源信号。仿真结果表明,本算法能够有效实现对源信号的有序分离,且分离精度很高。     

Improved statistical sparse decomposition principle method for underdetermined blind source signal recovery

Aiming at the statistical sparse decomposition principle (SSDP) method for underdetermined blind source signal recovery with problem of requiring the number of active signals equal to that of the observed signals, which leading to the application bound of SSDP is very finite, an improved SSDP (ISSDP) method is proposed. Based on the principle of recovering the source signals by minimizing the correlation coefficients within a fixed time interval, the selection method of mixing matrix's column vectors used for signal recovery is modified, which enables the choose of mixing matrix's column vectors according to the number of active source signals self-adaptively. By simulation experiments, the proposed method is validated. The proposed method is applicable to the case where the number of active signals is equal to or less than that of observed signals, which is a new way for underdetermined blind source signal recovery.     

Removal of the finite-distance source effect on the Applebaum array

The effect of a finite-distance signal source on the performance of an Applebaum array has been studied extensively in the literature. It has been concluded that unless the Applebaum array is focused at the exact source location, the degradation of the output signal-to-noise ratio (SNR) becomes unacceptable. The automatic focusing technique (AFT), developed for long-wavelength imaging systems using nonadaptive linear arrays, is extended here to focus adaptive arrays such as the Applebaum type. Thereafter, the far-field steering vector is used successfully to form a beam approaching the desired signal while suppressing the interferences. Substantial improvements in data processing have been achieved through the use of a partial convolution in the frequency domain. It is also demonstrated that the AFT can be used when the signal source range lies in the beginning of the Fresnel region of a nonadaptive linear array with negligible loss in the output SNR