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Results for “Analog-Digital Conversion”

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At least 487 records · Page 27Linked to original sources
PubMed1988

A home-based pulmonary function monitor for cystic fibrosis.

As care for the chronically ill makes increasing demands upon our medical system, cost-effective methods for addressing those demands are being sought. The use of self-monitoring coupled with telecommunication of results to the health-care provider can be expected to provide a partial solution in the appropriate clinical setting. An electronic spirometer with telecommunication ability for use by cystic fibrosis patients in the home has been developed.

Analog-Digital Conversion↗
PubMed1988

[Measuring signal processing by analog/digital conversion using personal computers. I: General principles].

Sampling rate, quantization noise and the number of channels to be acquired, the main concepts of computerized data acquisition, are discussed as regards their relevance to clinical research. Different setups of analog/digital conversion and signal processing, such as real-time and post-acquisition mode, are contrasted with respect to performance and installation effort. Additionally, continuous analog recording on FM coded tape is presented as a useful tool for software testing, re-evaluation and backup purposes.

Analog-Digital Conversion↗
PubMed1988

A method for improved biometry of the anterior chamber with a Scheimpflug technique.

A new method is described for obtaining cross-sectional images of the anterior chamber. Photographs are obtained with a Scheimpflug slit-lamp camera. After cornea, iris, and lens surfaces are digitized, mathematical corrections are made for the camera distortion and for the refractive effects of the cornea. The reproducibility and accuracy of the method were tested and found to be adequate for clinical study of human eyes in physiologic or diseased states.

Analog-Digital Conversion↗
PubMed1977

[Automatic analysis of gastrographies by means of optical digital equipment (author's transl)].

The present paper is concerned with problems of automatic analysis of radiograms, specially cinegastrographies. This study is connected with the utilisation of an interactive system including optical digitizer with its units of control and visualization. This system can explore the radiologic film in its current size of 30 X 40 cm. The particular interest of this application is extracting several parameters characterizing the size and the shape of the stomach. A middle axis can be extracted by computing, from this one a spatio-temporal diagram can be obtained. From this methodology of representation, several states of gastric motility could be characterized.

Analog-Digital Conversion↗
PubMed1987

A multichannel PWM telemetry system for kinematic gait analysis.

A multichannel biotelemetry system using pulse-width modulation-frequency modulation (PWM-FM) is described in detail for laboratory construction. Its application in a kinematic gait-analysis system is demonstrated, employing minimally encumbering electrogoniometry and foot-contact switches. The triaxial electrogoniometers sense rotational joint motion, and four foot-switches under the sole of each foot provide information on placement and temporal contact. Signals from the multiple sensors are amplified, encoded by pulse-width modulation, and transmitted at an FM radio frequency of 107 MHz. Received data are decoded and then sampled by a minicomputer for analysis. Results from a comparative study of kinematic gait in five normal subjects and five children with cerebral palsy demonstrate system effectiveness in providing quantitative data and various intrasubject and intersubject gait differences. Factors reviewed in the analysis include swing and stance times; cadence; hip-joint motion in sagittal, coronal, and transverse planes; and sequence of foot placement.

Analog-Digital Conversion↗
PubMed1987

Digital radiography.

Explore the source record for details and available documents.

Analog-Digital Conversion↗
PubMed1987

[Intravenous digital subtraction angiography].

Thanks to its high contrast resolution, intravenous digital subtraction angiography (IV-DSA) makes it possible to examine the arteries after injection of contrast media into a peripheral arm vein. IV-DSA is indicated in patients with clinical suspicion of arterial stenosis, occlusion, aneurysm or anomaly (ascending and descending aorta, aortic arch and its great vessels, and the renal, iliac, femoral and popliteal arteries). In many such patients, IV-DSA successfully replaces intraarterial catheter angiography. The advantages of IV-DSA (with a peripheral injection technique) as compared to conventional angiography, include its non-invasive character, a lower complication rate and less discomfort for the patient. The disadvantages of IV-DSA include poorer image quality due to lower concentration of contrast media in the vessels, reduced spatial resolution and the need for larger volumes of contrast media. The indication for conventional angiography is an inconclusive intravenous study due to motion artifacts and/or poor resolution.

Analog-Digital Conversion↗
PubMed1987

[Distributed automatic control system for experiments on the cultivation of microorganisms].

Hard- and software of a distributed system for computer control of experiments on cultivation of microorganisms is described. The system is based on microprocessor techniques and minicomputer CM-4(1420). It provides intensification of microbiological studies due to rational management of experiments, accumulation and long-term storage of experimental data and their processing with specific algorithms for providing additional information on biosynthetic processes and optimization of fermentation conditions.

Analog-Digital Conversion↗
PubMed1987

[Computer-assisted system for interstitial hyperthermia].

The combination of interstitial radiotherapy and interstitial hyperthermia is more promising in the treatment of tumors than one of these methods alone. The unit developed by us uses the afterloading needles for heating up the tumor tissue with ohm current and for controlling the distribution of temperature in the target volume. Up to twelve needles are provided by one commutator with the R.F. current controlled by the computer. The temperature is measured by three thermistors per needle which are arranged at an axial distance of 2 cm each. The linearization of the thermistor characteristics and the control of cummutator and R.F. generator is performed by the computer over an interface constructed by us. In order to achieve a homogeneous distribution of temperature in the target volume and to avoid hot spots, we have examined several needle configurations by measuring in an homogeneous phantom.

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