High-speed Data Recording Research Articles

Anisotropic nanostructure generated by a spatial-temporal manipulated picosecond pulse for multidimensional optical data storage.

Anisotropic nanostructures can be generated in fused silica glass by manipulating the spatiotemporal properties of a picosecond pulse. This phenomenon is attributed to laser-induced interband self-trapped excitons. The anisotropic structures exhibit birefringent properties, and thus can be employed for multi-dimensional optical data storage applications. Data voxels generated by such short laser irradiation enable on-the-fly high-speed data recording.

Distributed measurement system based on CAN data bus

PurposeThis paper aims to describe the idea behind and design of a miniaturized distributed measurement system based on a controller area network (CAN) data bus.Design/methodology/approachThe intention of the designers was to build a light and modular measurement system which can be used in remotely piloted aircraft systems and ultra-light aircraft during flight tests, as well as normal operation. The structure of this distributed measurement system is based on a CAN data bus. The CAN aerospace standard has been applied to the software as well as the hardware comprising this system. PRP-W2 software designed for PCs is an additional component of the proposed measurement system. This software supports data acquisition from a recorder unit and allows for preliminary data analysis, as well as data conversion and presentation.FindingsThe system, complete with a high-speed data recorder, was successfully installed on board of an MP-02 Czajka aircraft. A research experiment using the system and oriented on airframe high frequency vibration analysis is presented in the final part of this paper.Research limitations/implicationsThis measurement system allows analysis of high-frequency vibrations occurring at selected points of the aircraft. A data set is recorded by three-axis accelerometers and gyroscopes at frequencies up to 1 kHz.Practical implicationsThe use of a miniature and lightweight modular measurement system will, in many cases, be faster and less expensive than full-scale measurement and data acquisition systems, which often require a lengthy assembly process. The implementation of this class of lightweight flight test systems has many advantages, in particular to the operation of small aircraft. Such solutions are likely to become increasingly common in unmanned aerial vehicles and in other light aircraft in the future.Originality/valueThe adaptation of a distributed measuring system with a high frequency of measurements for purposes of small and miniature aircraft.

A 128-Channel FPGA-Based Real-Time Spike-Sorting Bidirectional Closed-Loop Neural Interface System.

A multichannel neural interface system is an important tool for various types of neuroscientific studies. For the electrical interface with a biological system, high-precision high-speed data recording and various types of stimulation capability are required. In addition, real-time signal processing is an important feature in the implementation of a real-time closed-loop system without unwanted substantial delay for feedback stimulation. Online spike sorting, the process of assigning neural spikes to an identified group of neurons or clusters, is a necessary step to make a closed-loop path in real time, but massive memory-space requirements commonly limit hardware implementations. Here, we present a 128-channel field-programmable gate array (FPGA)-based real-time closed-loop bidirectional neural interface system. The system supports 128 channels for simultaneous signal recording and eight selectable channels for stimulation. A modular 64-channel analog front-end (AFE) provides scalability and a parameterized specification of the AFE supports the recording of various electrophysiological signal types with 1.59 ± 0.76 root-mean-square noise. The stimulator supports both voltage-controlled and current-controlled arbitrarily shaped waveforms with the programmable amplitude and duration of pulse. An empirical algorithm for online real-time spike sorting is implemented in an FPGA. The spike-sorting is performed by template matching, and templates are created by an online real-time unsupervised learning process. A memory saving technique, called dynamic cache organizing, is proposed to reduce the memory requirement down to 6 kbit per channel and modular implementation improves the scalability for further extensions.

Improved High-Speed Data Recorder for Superconducting Digital-RF Receivers

A superconducting digital-RF receiver with high-ingest-rate data recording capability has been developed. The data recorder unit uses standard PC components with state-of-the-art solid-state drives (SSDs) and interfaces with the superconductor analog-to-digital converter (ADC) through a commercial FPGA board. High-speed data ingest rates exceeding 3.2 Gbps have been demonstrated successfully with single-bit ADCs clocked up to 27.52 GHz. A continuous recording of 2.5 TB has been achieved using a bank of 12 SSDs. A new graphical user interface featuring single button operation and automatic file naming, as well as convenient configuration setting, has been developed.

SpaceWire-based thermal-infrared imager system for asteroid sample return mission HAYABUSA2

A thermal-infrared (TIR) imager system is developed for HAYABUSA2, which is planned to be launched in 2014 and aims at sample-return from a C-class near-Earth asteroid 162173 (1999JU3) considered to contain organic or hydrated materials. The system consists of a TIR imager and digital electronics, which are used not only for the scientific investigation of physical properties of the asteroid surface, but also for the assessment of landing site selection and safe descent operation onto the asteroid surface with in situ measurement. TIR adopts an uncooled bolometer. Image operations such as multiple images summation, dark image subtraction, and the compensation of dead pixels are processed onboard. A processing module is connected to sensor interfaces through SpaceWire in order to provide deterministic processing time. Data compression is also provided to reduce the restriction of transmission time, which provides the equivalent compression ratio as JPEG2000 in 1/30 processing time in average. A high-speed data recorder is connected through SpaceWire in order to record TIR data in parallel with other sensor data. The modularity of SpaceWire enables us to use these as built devices for TIR and inherits the same design as the long-wavelength infrared imager developed for the Venus climate orbiter Akatsuki.

LIDAR, una tecnología de última generación, para planeación y desarrollo urbano

A typical LIDAR system rapidly transmits pulses of light that reflect off the terrain and other height objects. The return pulse is converted from photons to electrical impulses and collected by a high-speed data recorder. Since the formula for the speed of light is well known, time intervals from transmission to collection are easily derived. Time intervals are then converted to distance based on positional information obtained from GPS receivers and the on-board Inertial Measurement Unit (IMU) that constantly records the attitude of the aircraft. LIDAR systems collect positional and elevation data at pre-defined intervals. The resulting LIDAR data is a very dense network of elevation postings. The accuracy of LIDAR data is a function of flying height, laser beam diameter (system dependent), the quality of the GPS and IMU data, and post-processingprocedures. Accuracies of ±15cm (horizontally) and ±15cm (vertically) can be achieved. Accuracies better than 7cm (vertically) were achieved.

Over-500-Mbps Data Recording on Write-Once Media with L-Shaped Write Strategy

We have confirmed the necessary conditions to achieve data recording at a channel bit rate of over 500 Mbps. We discuss the approaches and experiments adopted to realize such high-speed data recording by way of present available techniques. In order to clarify the necessary conditions for them, we have investigated the laser response speed required for recording, optimum write strategy and suitable media for high-speed mark formation. As a result of these studies, the over-500-Mbps data recording was realized by applying a new L-shaped write strategy with a laser pulse of 0.7 ns rising time to Te–O–Pd write-once media of the Blu-ray Disc format.

High Speed Data Recording: Digital VTRs Find New Applications

Entertainment production, be it cinema, television, or even “game” software, is turning increasingly to computer-generated or manipulated information. Computer processing and digital manipulation has permitted the creation of images otherwise impossible, the production of effects not otherwise practical, and correction of innumerable image defects large and small. Given this combination of voluminous data and expensive hardware, the industry faced a dilemma: how to “move” jobs in and out of a facility quickly so the equipment could be made available to other clients and projects. Existing small format data recorders generally have proven unsatisfactory for these purposes due to the limited data rates and media size. Current digital videotape recorders are now capable of data rates well in excess of 200 Mbits/sec (25 Mbytes/sec). Unfortunately, some recorders incorporate data compression, rendering them suitable only for traditional video. Other video formats have been customized and repurposed for data recording, hut these machines are no longer applicable for video recording. As the boundaries between the computer and video worlds blur, users need multipurpose solutions for both fast data storage of nonrasterized image information and high-quality conventional video storage. Full bit-rate uncompressed digital video recorders can provide the desired performance capabilities for both video and high-performance data recording, allowing dual-purpose use of the same transport and cassettes. Panasonic developed the D-5 (uncompressed 10-bit ITU-R 601) videotape recorder (VTR) format for high-end video post-production, and it has met with wide acceptance. The Viewgraphics (Mountain View, Calif.) “Dataview” is an industry-standard computer bus (VME) interface device developed to allow large data files to be recorded on unmodified D-5 VTRs and to allow video to be input as data into platforms like the Silicon Graphics Onyx and Challenge. This paper describes the D-5 format, the Viewgraphics Dataview adaptor, and data recording on videotape.

ディジタル画像記録を目的とした高速データレコーダの実験

An experimental model of a high speed data recorder which records compressed HDTV images is developed. This data recorder is capable of recording digital data up to 140 Mbps in a cassette-type half-inch tape for 60 minutes, and is applicable to various transmission rates less than 140 Mbps by changing an interface board. In this data recorder, a double Reed-Solomon code is used as an error correction code. Record equalization is employed to reduce the channel bit error rate. With this method, a channel bit error rate of 10-5-10-4 is obtained. An off track margin of ± 5μm is obtained, to keep the channel bit error rate at less than 10-4. The channel bit error rate degrades in a low humidity condition caused, in our estimation, by an increase of a rubbing noise. When recorded HDTV image data is compressed with HDTV-CODEC, our experimental model gives playback data without degrading the coded picture quality.

Applications of microcomputer-based systems in power substations

Three applications of microprocessors in power substations are presented. The use of the processors for metering, high-speed data recording, and distribution feeder automation is described. Emphasis is placed on those functions which could not be performed if microprocessor-based design architectures were not utilized. Specific information is given concerning substation hardware. The advantages of microprocessor-based designs are discussed, and details are given of the performance of field installations. >

Laser diode uses for optical disks

Summary form only given, as follows. Semiconductor lasers are key devices in optical disks. Optical properties of transverse mode-controlled diode lasers, such as far-field beam pattern, output power, spectrum, astigmatism, polarization, lifetime, and temperature dependencies for these characteristics are presented in this paper. Their use in optical heads has been improved in three respects: (1) Longitudinal mode instability causes noise in the output power. Therefore an appropriate length between the diode and theoretical disk was determined. (2) For diode laser recording, beam profile conversion from an elliptic to a circular profile was accomplished by using two prisms without optical loss. (3) The objective lens was actuated radially and vertically for tracking and focusing, instead of actuating it wholly. This has several advantages, such as easier laser diode cooling, high speed data recording and playback, and simple objective lens configuration. A means to reduce tracking offset error, due to radial displacement of an objective lens, is discussed.