Microprocessor Controlled Data Acquisition System Research Articles

A fast microprocessor controlled data acquisition system for high resolution Mössbauer spectroscopy

We describe a microprocessor controlled data acquisition system designed for Mossbauer spectroscopy which operates in both pulse height analysis and multichannel scaling with high counting rate (> 20 MHz) and resolution (up to 8192 channels per spectrum). The apparatus makes use of two counters and of a double memory block. It is thus possible to obtain a minimum channel-advance dead-time lower than 50 nsec and a minimum dwell-time of 1 μsec. The accumulated data are transferred to a microcomputer for storage and analysis from one of the two blocks while the other continues the acquisition process. The system is totally programmable, and all the acquisition parameters can be easily selected in a wide range.

A battery operated bubble memory data-acquisition system

A low-power microprocessor-controlled data-acquisition system, using nonvolatile bubble memory cartridges for mass data storage, is described. The system is battery powered and can operate unattended in a field environment for two months. An analog voltage, which is derived from a gamma-ray ionization chamber or other moderately high-output transducer, is the system input. By using CMOS technology and power switching techniques, the system achieves very low power consumption ( >

A Back-Portable Microprocessor-Based Impulse Radar System

We have developed and tested a portable impulse radar for ground-based sounding of glaciers. Noteworthy characteristics of the instrument are its portability, low power consumption, digital data storage, and the ability to be operated either manually or automatically under program control. Current system specifications include a band width of 46 MHz; a sampling interval of 10.76 ns; depth precision of 0.9 m; 1024 samples per record; amplitude resolution of 8 bits; minimum recordable signal at the receive antenna equal to 0.26 mV; an operating center frequency of 8.5 MHz and an antenna-damping coefficient of 300 ohms. The transmitter uses paired SCRs and a 12 V to 800 V converter to impress a 1200 V step on to a resistively damped dipole antenna. This pulse is triggered from the receiving system via a fibre optics cable so that each record can include the complete surface-path wavelet. The receiver unit combines a wide-band amplifier (with variable front-end attenuation) with a microprocessor-controlled data-acquisition system of our own design. The result of each sounding can be replayed as an “A-scope” display on a small, low-cost oscilloscope and stored on or retrieved from digital cassettes. In the unattended mode, records are collected at programmable intervals. The system weighs about 7.5 kg and uses dry cells or rechargeable batteries for power. Examples were presented in a poster session of sounding profiles taken in July 1986 on Trapridge Glacier, Yukon Territory in Canada, along lines coinciding with an extensive drilling program. Although not yet fully analysed, we feel that some of the results may represent the effects of crevasses, internal features such as morainal material, varying bed features, and changes in subglacial and englacial hydrology.

A Back-Portable Microprocessor-Based Impulse Radar System

We have developed and tested a portable impulse radar for ground-based sounding of glaciers. Noteworthy characteristics of the instrument are its portability, low power consumption, digital data storage, and the ability to be operated either manually or automatically under program control. Current system specifications include a band width of 46 MHz; a sampling interval of 10.76 ns; depth precision of 0.9 m; 1024 samples per record; amplitude resolution of 8 bits; minimum recordable signal at the receive antenna equal to 0.26 mV; an operating center frequency of 8.5 MHz and an antenna-damping coefficient of 300 ohms.The transmitter uses paired SCRs and a 12 V to 800 V converter to impress a 1200 V step on to a resistively damped dipole antenna. This pulse is triggered from the receiving system via a fibre optics cable so that each record can include the complete surface-path wavelet. The receiver unit combines a wide-band amplifier (with variable front-end attenuation) with a microprocessor-controlled data-acquisition system of our own design. The result of each sounding can be replayed as an “A-scope” display on a small, low-cost oscilloscope and stored on or retrieved from digital cassettes. In the unattended mode, records are collected at programmable intervals. The system weighs about 7.5 kg and uses dry cells or rechargeable batteries for power.Examples were presented in a poster session of sounding profiles taken in July 1986 on Trapridge Glacier, Yukon Territory in Canada, along lines coinciding with an extensive drilling program. Although not yet fully analysed, we feel that some of the results may represent the effects of crevasses, internal features such as morainal material, varying bed features, and changes in subglacial and englacial hydrology.

Sample Averaging and Rectify, Integrate, and Dump for Synchronous Demodulation Measurement of Mean Radiation

A subsystem which implements two approaches for the synchronous demodulation and measurement of the mean intensity of chopped solar radiation has been designed and built as part of a microprocessor-controlled data acquisition system for the Laser Heterodyne Spectrometer (LHS) instrument built at NASA Langley Research Center, Hampton VA. One approach is based on a commonly used analog technique consisting of full-wave rectification followed by a fixed-interval integrate and dump. The alternate approach consists of a simple amplifier/filter whose output is synchronously sampled, digitized, and averaged. The two approaches are presented and the noise performance compared analytically and empirically. Pertinent issues of performance and implementation are discussed. The complete measurement subsystem is described briefly.

A fast data acquisition system for PHA and MCS measurements

A microprocessor controlled data acquisition system for pulse height analysis and multichannel scaling is described. A 4K×24 bit static memory is used to obtain a fast data acquisition rate. The system can store 12 bit ADC or TDC data within 150 ns. Operating commands can be entered via a small keyboard or by a RS-232-C interface. An oscilloscope is used to display a spectrum. The display of a spectrum or the transmission of spectrum data to an external computer causes only a short interruption of a measurement in progress and is accomplished by using a DMA circuit. The program is writtenin Modular Pascal and is divided into 15 modules. These implement 9 parallel processes which are synchronized by using semaphores. Hardware interrupts from the data acquisition, DMA, keyboard and RS-232-C circuits are used to signal these processes.

A microprocessor system for Eddy-correlation

The application of a microprocessor-controlled data acquisition and processing system is described. The system, which is battery powered, takes data from six sensors at a frequency of 10 Hz and computes the fluxes of heat, water vapour and momentum in real time, using the eddy correlation method. From results obtained at a field site, the microprocessor system is separately compared with a proven off-line eddy-correlation system and with measured net radiation. These tests indicate that, provided care is taken in interpreting the data in terms of the performance and exposure of the sensors, the system described is capable of adequately measuring energy fluxes at unattended sites.

Microprocessor controlled data acquisition system for radio propagation measurements

At the Compañía Telefónica Nacional de España, a microprocessor controlled data adquisition instrument, allowing for the storage of collected data on a digital cassette magnetic tape, has been designed and built. By this means, a great increase of unattended operation time and easier programming of measurements configurations is achieved, as well a better computer data processing capability.

Microprocessor-controlled acquisition system for the determination of MOS transistor parameters

Discusses a microprocessor-controlled data acquisition system for automated acquisition of MOS transistor parameters. The Analog Signal Processor and the Control Interface Circuit are described. Finally, the authors explain the procedure of parameter determination based on the least squares estimation criterion. This procedure is applied to long-channel, surface-channel, enhancement-mode PMOS transistors. The <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">I</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">D</sub> - <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">D</sub> curves exhibit an accuracy of 1-3 percent compared with the experimental characteristics.

Data acquisition system with 8 BIOMATION 8100 controlled by a 6800 microcomputer

A 6800 microprocessor controlled data acquisition system with 8 BIOMATION 8100 transient recorders is described. The system allows programming the transient recorders and storing data on tape cassettes or punched tape for further computation. The system has been used successfully in shock tube experiments and for measuring shock pressures in solids by carbon resistors.

Digital Multiplexing of Analog Data in a Microprocessor Controlled Data Acquisition System

An analog data acquisition system typically consists of an analog multiplexer followed by an analog to digital (A/D) converter. An alternative configuration uses multiple comparators (one per input) followed by a digital multiplexer. If the control functions for A/D conversion are incorporated into a microprocessor, several potentially interesting data acquisition and conversion strategies are available. At first thought, an interrupt-driven conversion process which simultaneously searches all inputs in parallel for a level match appears attractive. However, analysis shows that a sequential conversion of the inputs, one at a time, using the successive approximation algorithm, is usually superior.

Digital Multiplexing of Analog Data in a Microprocessor Controlled Data Acquisition System

An analog data acquisition system typically consists of an analog multiplexor followed by an analog to digital (A/D) converter. An alternative configuration uses multiple comparators (one per input) followed by a digital multiplexor. If the control functions for A/D conversion are incorporated into a microprocessor, several potentially interesting data acquisition and conversion strategies are available. At first thought, an interrupt-driven conversion process which simultaneously searches all inputs in parallel for a level match appears attractive. However, analysis shows that a sequential conversion of the inputs, one at a time, using the successive approximation algorithm, is usually superior.

Improved microprocessor-controlled pedestrian data-acquisition system

In a previous letter a novel pedestrian data acquisition system was described. Inclusion of a microprocessor has since resulted in portable self-contained inexpensive instrumentation. Additional hardware redundancies have been included to improve the count accuracy at junctions and bends. A superior recording format has increased the efficiency of the system.

Microprocessor-Controlled Data Acquisition System for Pulsed Laser Spectroscopy

Pulsed laser systems produce spectroscopic signals with large shot-to-shot variations, short durations, and low duty cycles. The most satisfactory signal processing system is gated integration, with pulse averaging and ratioing to a reference signal. We describe a system based on commercially available modular integrators and a hobbyist microcomputer which performs the averaging and ratioing digitally. System performance is equal to or better than that of fully analog systems, while the cost is low and construction is straightforward.