Development of a Digital Signal Processing System for the X-Ray Microcalorimeter Onboard ASTRO-H (II)

The Pulse Shape Processor is a digital signal processing electronics for the microcalorimeter instrument onboard ASTRO-H. Receiving digitized waveform (14?bit, 12.5?kHz sample) from 2×18 channels, two identical units of PSP-A and -B trigger X-ray events, assign five kinds of event grade, and perform optimal filtering to measure energy deposit on the 6×6 microcalorimeter pixels. One unit of PSP is composed of one FPGA board and two CPU boards. This paper describes the event processing algorithm to fulfill requirements for the signal processing, and task sharing between FPGA and CPU.     

A Digital Signal Processing Instrument for Real-Time Phase Noise Measurement

A digital-signal-processing-based instrument for phase noise measurement on sinusoidal signals is described. It incorporates a special hardware architecture, which is made up of a core digital signal processor that is connected to a data acquisition board, and takes advantage of a new measurement procedure based on a quadrature demodulation scheme, which has been proposed by the authors. Thanks to an optimized implementation of this procedure, the instrument exploits all its hardware resources to achieve high performance and real-time operation. For input frequencies of up to some hundreds of kilohertz, the instrument proves to be capable both of updating phase noise power spectrum while seamlessly capturing the analyzed signal into its memory and of granting frequency resolution as good as a few units of hertz.      

一种新颖的科氏流量计数字信号处理方法

利用矩形自卷积窗对谐波和白噪声的抑制作用,加窗进行短时傅里叶变换能很好的跟踪测量信号频率,而且加窗后的信号能直接用于滑动Goertzel算法测量相位差的特性,提出了一种新的科氏流量计信号处理方法.仿真结果表明整个信号处理算法的测量精度高,实时性好,便于系统实现.     

Kilopixel X-ray Microcalorimeter Arrays for Astrophysics: Device Performance and Uniformity

We are developing kilopixel arrays of TES microcalorimeters to enable high-resolution x-ray imaging spectrometers for future x-ray observatories and laboratory astrophysics experiments. Our current array design was targeted as a prototype for the X-ray Microcalorimeter Spectrometer proposed for the International X-ray Observatory, which calls for a 40×40-pixel core array of 300?μm devices with 2.5?eV energy resolution (at 6?keV). Here we present device characterization of our 32×32 arrays, including x-ray spectral performance of individual pixels within the array. We present our results in light of the understanding that our Mo/Au TESs act as weak superconducting links, causing the TES critical current (I _c ) and transition shape to oscillate with applied magnetic field (B). We show I _c (B) measurements and discuss the uniformity of these measurements across the array, as well as implications regarding the uniformity of device noise and response. In addition, we are working to reduce pixel-to-pixel electrical and thermal crosstalk; we present recent test results from an array that has microstrip wiring and an angle-evaporated copper backside heatsinking layer, which provides copper coverage on the four sidewalls of the silicon wells beneath each pixel.     

maXs: Microcalorimeter Arrays for High-Resolution X-Ray Spectroscopy at GSI/FAIR

Highly-charged heavy ions like U⁹¹⁺ provide unique conditions for the investigation of relativistic and quantum electrodynamical effects in strong electromagnetic fields. We present two X-ray detectors developed for high-resolution spectroscopy on highly-charged heavy ions. Both detectors consist of metallic magnetic calorimeters (MMCs) forming linear eight-pixel arrays. The first detector, maXs-20, is developed for the detection of X-rays up to 20?keV with an energy resolution below 3?eV. The second device, maXs-200, is designed for X-ray energies up to 200?keV with an energy resolution of 40?eV. The results of characterization measurements of single detectors of both arrays will be shown and discussed. In both cases, the performance of the detectors agrees well with their design values. Furthermore, we present a prototype MMC for soft X-rays with improved magnetic flux coupling. In first characterization measurements the energy resolution of this device was 2.0?eV (FWHM) for X-rays up to 6?keV.     

Automated Hybridization of X-ray Absorber Elements A Path to Large Format Microcalorimeter Arrays

We have developed an automated die-scale process for the attachment of X-ray absorbers onto microcalorimeters. Here, we describe the process for the production of absorber tiles on a handle wafer, their attachment to the microcalorimeter, and the removal of the supporting handle wafer. The process is shown to be a robust path to large format arrays of microcalorimeters.      

光纤准白光干涉信号数字化处理方法

提出一种光纤准白光干涉信号数字化处理方法。该方法采用干涉条纹脉冲实现干涉包络信 号同步采集,克服了导轨移动速度不均匀造成的影响;通过高斯函数曲线拟合方法高精度确定干涉信号零光程差点;大大提高了准白光干涉信号定位精度。为消除包络信号采样边界点不确定性带来的误差,采用外插法进行补偿。实验表明,采用该方法对光纤准白光干涉信号零光程差位置的定位精度优于0.5个干涉条纹。     

High-Resolution Ugtrasonic Spectrometer Using Digital Signal Processing

We have developed an ugtrasonic system for high-resolution sound velocity and attenuation measurements using a phase-sensitive, time-of-flight technique. Signal processing, implemented in Lab VIEW, is done entirely after digitization, removing the need for analog mixers and figters. At a signal level of 10 pW, the phase resolution is better than 10^?3 rad, and the signal-to-noise ratio in amplitude is better than 60 dB after averaging 400 acquisitions.     

一种科氏流量计的数字信号处理与驱动方法研究

数字信号处理和数字驱动是科里奥利质量流量计的发展趋势。研究了基于同步调制的数字信号处理方法，进行公式推导、性能分析和计算机仿真。研究数字驱动方法并利用数字控制方法提高流量管的起振性能，给出了数字驱动方案。     

采用数字信号处理器的空间同步检测轮廓术

提出一种空间同步检测轮廓术的硬件实现方案,利用数字信号处理器（ＤＳＰ）强大的数据处理能力来解决三维面形测量中数据量大和实时性差之间的矛盾。文中讨论了ＦＩＲ滤波器的设计方法,以及用ＤＳＰ器件的实现方法。实验结果验证了所提方案是可行的。文中还讨论了改善系统性能的途径。     

A Versatile Biomolecular Charge-Based Sensor Using Oxide-Gated Carbon Nanotube Transistor Arrays

Label-free deoxyribonucleic acid (DNA) hybridization detection using carbon nanotube transistor (CNT) arrays is demonstrated. The present scheme is distinguished from other CNT sensing methods as it uses a gate oxide overlayer on top of the carbon nanotubes, which function solely as charge sensors but are not participants in the chemical binding process. Because it involves DNA probe attachment on the gate oxide rather than on the CNT, this approach allows the use of conventional DNA functionalization and bioassay protocols, and is less prone to false positives. The signal sought is a few tens of millivolts in threshold voltage shift due to the increase of surface charges after target hybridization. The hybridization detection is shown to be highly specific and sensitive to a minimum concentration of about 30 nM of 61-mer DNA. Despite differences in the transistor properties due to the spread in the CNT parameters during fabrication, the yields are very high and the sensing characteristics are uniformly consistent in nearly all transistors.     

基于nRF903的无线数传模块设计

本文介绍了采用nRF903和P89LPC932构成的无线数传模块,该模块接口电路简单可靠,并能实现低功耗工作。可适用于无线通信系统。     

声学信号处理中并行计算系统设计

在声学信号处理、科学计算、仿真模拟、图像处理及实时信号处理领域,对处理速度的要求极为迫切,满足对运算速度的巨大需求很大程度只能通过并行处理技术来实现.本文讨论基于多ADSP21060的数字信号并行处理系统设计和软件开发方法,并进行性能分析.     

Optimal Perturbation Signal Waveform for Sensing Arrays

The optimal solution of perturbation signal waveform used to linearize the nonlinear transfer characteristic of the receptor array for an image sensing is sought through approximation. A completely linearized characteristic is obtained for the one-dimensional square-element receptor array without dead space by introducing this optimal perturbation signal to the system. Therefore, a zero sensing error is achieved. The result is extended to linearize one-dimensional receptor arrays having specific dead space and two-dimensional receptor arrays.     

一种针对频率扫描测量系统的信号处理方法

设计了一种针对频率扫描绝对距离测量系统的信号处理算法。该系统采用基于电流调制式的频率扫描方法,利用一个比对干涉光路与一个测量干涉光路进行同步测量。两路扫描干涉信号分别由两个光电探测器进行光电转换,作为绝对距离计算处理的输入信号。分析了测量系统的原理与扫描干涉信号的特点,应用两步差分卷积算法进行信号处理,提取的比对光路与测量光路的周期或频率信息进行绝对距离测量。分析了该算法的周期计算误差。实验验证这种方法具有较大的计算优势。     

Hilbert-Huang变换在剪力称重轨测试信号处理中的应用

探讨用一种新方法Hilbert Huang变换对平稳检测信号进行分析 ,着重论述了它在新型剪力称重轨轮扫描检测信号数字处理中的应用及从轮扫描信号中准确的提取称重信号的原理。     

Electroplated Indium Bumps as Thermal and Electrical Connections of NTD-Ge Sensors for the Fabrication of Microcalorimeter Arrays

We are developing a method to build arrays of Ge-based microcalorimeters for soft X-rays detection using micro-photolithographic techniques. A key element of the process is the electrical and thermal connection between the germanium sensors and the interconnection electrical tracks, that lay on a substrate acting as mechanical support and thermal sink. The geometry of the sensors, that have a square base truncated pyramid shape, makes feasible a connection through indium soldering. We describe a technique, based on microlithography and electroplating, adopted to grow indium bumps of a few tens of square microns of area and several microns high on top of the contact pads patterned on the substrate. The sensor array is placed over the bumps and a subsequent baking melts the indium, soldering the sensors to the pads.