Commercial Data Acquisition System Research Articles

A portable telemetry system for brain stimulation and neuronal activity recording in freely behaving small animals

A portable multi-channel telemetry system which can be used for brain stimulation and neuronal activity recording in freely behaving small animals is described here. This system consists of three major components of headstage, backpack and portable Personal Digital Assistant (PDA). The headstage contains high precision instrument amplifiers with high input impedance. The backpack is comprised of two parts: (1) a main board (size: 36 mm × 22 mm × 3.5 mm and weight: 40 g with batteries, 20 g without), with current/voltage stimulator and special circuit suitable for neuronal activity recording and (2) and a bluetooth transceiver, with a high data transmission rate up to 70 kb/s, suitable for downloading stimulation commands and uploading acquired data. We recorded neuronal activities of the primary motor area of a freely behaving rat with 12-bit resolution at 12 k samples/s. The recorded data and analysis results showed that the system was successful by comparing with the commercial equipment Cerebus™ 128-Channel Data Acquisition System (Cyberkinetics Inc.). Using the PDA, we can control stimulation and recording. It provides a flexible method to do some research work in the circumstances where other approaches would be difficult or impossible.

Review of signal distortion through metal microelectrode recording circuits and filters

Interest in local field potentials (LFPs) and action potential shape has increased markedly. The present work describes distortions of these signals that occur for two reasons. First, the microelectrode recording circuit operates as a voltage divider producing frequency-dependent attenuation and phase shifts when electrode impedance is not negligible relative to amplifier input impedance. Because of the much higher electrode impedance at low frequencies, this occurred over frequency ranges of LFPs measured by neurophysiologists for one head-stage tested. Second, frequency-dependent phase shifts are induced by subsequent filters. Thus, we report these effects and the resulting amplitude envelope delays and distortion of waveforms recorded through a commercial data acquisition system and a range of tungsten microelectrodes. These distortions can be corrected, but must be accounted for when interpreting field potential and spike shape data.

EVALUATION OF A PC-BASED DATA ACQUISITION SYSTEM FOR LONG-TERM RECORDING OF ACTION POTENTIALS WITH MINIMAL DEDICATED CIRCUITS

Owing to the improvement of computing power, computer-aided multi-unit acquisition and separation rapidly proliferated during the last two decades. To utilize this technology is, however, not easy since task-specific designs are usually mandatory. To overcome this obstacle, a commercial data acquisition system was used to evaluate whether it is possible to accomplish the task of multi-unit acquisition without the aid of these devices. As the results shown that the technique of spike-trigger acquisition can provide the capability to reduce the data amount to 2% while compared with that sampled by continuous acquisition. However, the interval between two consecutive spikes cannot be shorter than 5 ms. This suggests that special designed devices are still necessary.

The role of modal analysis in stringed instrument design

The modal response of stringed instruments clearly contributes to sound quality. Modal analysis was applied to stringed instruments shortly after commercial data acquisition system became available. Even now, the most sophisticated equipment has been used on instruments. In spite of this effort, there is no consensus on the relationship between modal behavior of an instrument and sound quality. Useful guidelines have been developed for the lower modes of guitars and violins, but these are necessary, not sufficient conditions for superior sound quality. It now appears that superior sound quality is based on more subtle interactions of the dynamic response of the acoustically coupled structure and its material properties. Understanding the modal response of the instrument is still extremely useful. The acoustic-structure interaction of the first two or three modes of the instrument clearly demonstrates the basic physics and forms the basis of discrete models that are very helpful in considering the first-order effects of instrument modifications. The modal response of an instrument can also be critical in placing sensors to be used as pickups. Accelerometers are being used to augment piezoelectric bridge pickups and more traditional inductance pickups and their placement greatly affects the resulting sound quality.

The control system for the ATLAS pixel detector

A pixel detector is under construction for A Toroidal LHC ApparatuS (ATLAS) experiment, which will utilize the large hadron collider (LHC) at Conseil Europe/spl acute/enne pour la Recherche Nucle/spl acute/aire (CERN). Due to the large number of channels, a data-intensive control system will be required. The choice and design of the requisite hardware for this control system is mainly driven by a high power density and a harsh radiation environment. This includes the development of an interlock system to ensure the safety of the detector, and a special control and supply system for the operation of the optical link connection to the data acquisition (DAQ) readout chain. Given the complexity of the required assembly, a commercial supervisory control and data acquisition (SCADA) system is used. Based on this, we have developed a geographical approach, which matches the different hardware components for the operation of one detector part to uniform software elements. Its tree structure allows clear control of a large amount of information. For the final design, where several SCADA systems are linked, a distributed system is necessary. We have shown this system to work efficiently and will discuss first experiences.

Automation and Control of an Imaging Internal Laser Desorption Fourier Transform Mass Spectrometer (I2LD-FTMS)

This paper describes the automation of an imaging internal source laser desorption Fourier transform mass spectrometer (I2LD-FTMS). The I2LD-FTMS consists of a laser-scanning device [Scott and Tremblay, Rev. Sci. Instrum. 2002, 73, 1108–1116] that has been integrated with a laboratory-built FTMS using a commercial data acquisition system (ThermoFinnigan FT/MS, Bremen, Germany). A new user interface has been developed in National Instrument's (Austin, Texas) graphical programming language LabVIEW to control the motors of the laser positioning system and the commercial FTMS data acquisition system. A feature of the FTMS software that allows the user to write macros in a scripting language is used creatively to our advantage in creating a mechanism to control the FTMS from outside its graphical user interface. The new user interface also allows the user to configure target locations. Automation of the data analysis along with data display using commercial graphing software is also described.

Automation and Control of an Imaging Internal Laser Desorption Fourier Transform Mass Spectrometer (I2LD-FTMS)

This paper describes the automation of an imaging internal source laser desorption Fourier transform mass spectrometer (I2LD-FTMS). The I2LD-FTMS consists of a laser-scanning device [Scott and Tremblay, Rev. Sci. Instrum.2002, 73, 1108–1116] that has been integrated with a laboratory-built FTMS using a commercial data acquisition system (ThermoFinnigan FT/MS, Bremen, Germany). A new user interface has been developed in National Instrument's (Austin, Texas) graphical programming language LabVIEW to control the motors of the laser positioning system and the commercial FTMS data acquisition system. A feature of the FTMS software that allows the user to write macros in a scripting language is used creatively to our advantage in creating a mechanism to control the FTMS from outside its graphical user interface. The new user interface also allows the user to configure target locations. Automation of the data analysis along with data display using commercial graphing software is also described.

Controlling front-end electronics boards using commercial solutions

LHCb is a dedicated B-physics experiment under construction at CERN's large hadron collider (LHC) accelerator. This paper will describe the novel approach LHCb is taking toward controlling and monitoring of electronics boards. Instead of using the bus in a crate to exercise control over the boards, we use credit-card sized personal computers (CCPCs) connected via Ethernet to cheap control PCs. The CCPCs will provide a simple parallel, I2C, and JTAG buses toward the electronics board. Each board will be equipped with a CCPC and, hence, will be completely independently controlled. The advantages of this scheme versus the traditional bus-based scheme will be described. Also, the integration of the controls of the electronics boards into a commercial supervisory control and data acquisition (SCADA) system will be shown.

A flow cytometer designed for fluorescence calibration.

In the development of suitable standards and calibration materials for fluorescence measurement, it becomes necessary to make accurate fluorescence measurements of these materials on flow cytometers. The results of such measurements may be affected by numerous sources of error, prominent among which are deviations of logarithmic amplifiers (log amps) from ideal response. To minimize the deleterious effects of log amps and multicolor fluorescence compensation circuitry on measurements, we built a flow cytometer with electronics incorporating high-precision peak detectors usable over a range from below 2 mV to 10 V, and we developed data acquisition software that transfers held peak values to a commercial 16-bit data acquisition system mounted in a personal computer running Windows 95. Fluorescence compensation is done in software, and transformation of the compensated data from a 16-bit linear to an 8-bit, 4-decade logarithmic scale is accomplished using a look-up table. Although dynamic range may be restricted by noise in the data acquisition system, high sensitivity can be achieved by photomultiplier tube gain adjustment, and it is likely that the use of a lower noise data acquisition system and/or digital processing of pulse information will enable operation over the full 4-decade dynamic range. Even at its current performance level, our instrument provides substantially better linearity over most of the scale than can be obtained using conventional electronics incorporating log amps; we believe this characteristic is critical for use in standards development.

Signal filtering of potentiometric stripping analysis using Fourier techniques

Four filtering functions, rectangular, triangular, exponential and decay exponential for Fourier filtering have been compared in this study of potentiometric stripping analysis (PSA) data. The filtering procedure involves treating the potential coordinate as mathematically equivalent to a time coordinate to transform data to the frequency domain. After Fourier transformation, each method yielded signal-to-noise enhancement over the original data in the order, decay exponential > triangular > exponential > rectangular. Apart from the filtering functions, two different filtering procedures, conventional and reflectance, have been compared in this study. Peak area measurement was unaffected by the reflectance procedure, while an undesirable increase in peak area was observed in the conventional procedure. A linear peak area-concentration relationship was retained in all cases. The resolution of overlapping potential peaks, using copper and bismuth peaks as the example, was most improved using the rectangular filtering function and worst using the decay exponential filtering function. This is completely opposite to the results obtained in signal-to-noise enhancement study. Thus, a compromise between S N ratio enhancement and peak distortion has to be made, as the latter is always a trade-off in signal processing. With the use of a personal computer (PC) and commercial data acquisition systems, the original saved data can be stored. Selection of a particular type of filtering function to optimise the analytical signal can be achieved by applying various functions to the original signal, until a desirable output is obtained.

Holistic design of a scanning nuclear microprobe

A scanning nuclear microprobe (SNM) has been designed to focus high flux densities of protons to 1 μm in vacuum and to 25 μm in air or controlled atmospheres. The design was constrained by demanding that the market price of a commercial SNM, including end-station, scanner, automated control and data acquisition system, be ≤ 1 million US dollars. This goal can be achieved with a single-ended electrostatic accelerator delivering proton and alpha beams up to 1.5 MeV. The holistic design not only substantially reduces the cost of the overall system but allows all elements in the system — ion source, velocity selector, accelerator, magnetic focusing and scanner — to be optimized. We find that it should be possible to obtain 2 nA of 1.5 MeV protons in a 1 μm target spot; i.e. an order of magnitude improvement over existing systems. Such beam densities will make the SNM a versatile tool for studies in the few hundred nanometer range.

Software for personal instruments

When a personal computer (PC) is used as the computing system of an intelligent instrument, software devoted to measurement process control and to measurement process outputting can be specially developed to assist the operator throughout the measurement process in a friendly way. When these conditions are met, the intelligent instrument is called a personal instrument (PI). The main features of a PI are discussed, and the requirements for PI software are given. The performance of an original software package for PI is illustrated, showing how all the requirements are satisfied. This software, coupled to a good commercial data acquisition system, features high-precision measurement and a high level of friendliness and can be useful for lab tests and educational purposes. For lab tests, this software is a good basis for an automatic test station with extended help facilities. It ensures better performances than that of a digital scope because it allows dedicated measurement routines to be developed and executed. The software is effective for educational applications, since it allows direct application of all capabilities offered by computers in instrumentation, when associated with suitable A/D (analog/digital) conversion hardware. >

An improved thermobalance for fluorination of carbon

A design of a thermobalance for study of fluorination of carbon is discussed. A beryllium-copper spring balance and a linear variable differential transformer (LVDT) are used as the sensing mechanism to monitor weight change and thus measure the extent of the reaction. Corrosion problems are overcome by previous passivation of these items. The sealable nature of this thermobalance allows a complete mass balance for the kinetic study. Data are acquired by a microcomputer connected to the balance through a commercial data acquisition system, and the reaction rate profile is computed immediately after completion of the reaction.