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Results for “Analog-Digital Conversion”

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At least 991 records · Page 55Linked to original sources
PubMed1981

Digital scintigraphy: principles, design, and performance.

In a digital camera the position of a scintillation event is computed following analog-to-digital conversion of photomultiplier pulse charges. Digital position analysis is essentially a mathematical inversion procedure based upon calibrated responses of the photomultipliers to scintillations from a narrow-beamed source that maps a detector's field of view. Operationally, a camera's image characteristics are optimized by means of computer-generated inversion reference tables, individually tailored to the specific response characteristics of each detector. Design considerations indicate that cameras of varied configurations, e.g., linear, disc-shaped, rectangular, or cylindrical, can be analyzed by this method. Also, for any given electro-optical system, energy resolution, spatial characteristics, and event-rate performance can be made superior to analog systems. The measured performances of a one-dimensional test camera, although limited in its optical and electronic design, support this conclusion.

Analog-Digital Conversion↗
PubMedDate not supplied

[Devices for visualizing biosignals for the comprehensive equipping of cardiology institutions].

Purposeful activity of the Scientific-Production Association of Radioelectronic Medical Equipment in the creation, serial tissue and practical mastering of to-day's aids of biosignal visualization allows, in optimal way, realizing complete instrumentation of major links in cardiological service. Further perfection of these facilities is directed to more efficient diagnostic value of visible information, to acceleration of diagnostic process and its simplicity.

Analog-Digital Conversion↗
PubMedDate not supplied

[Quality improvement of the medical images in digital and optoelectronic devices].

The realization of image processing algorithms in a hybrid optoelectronic device is discussed. The linear part of the algorithm is carried out in the optical block, and the nonlinear part of the algorithm in the electronic processing block of the device. These studies indicate the expediency of using the optical methods for processing the images of medico-biological objects to facilitate their visual analysis.

Analog-Digital Conversion↗
PubMed1981

[Derived potentials and the microcomputer (author's transl)].

A method for conducting "brain stem early derived potentials" using an inexpensive microcomputer is described. This type of examination is, however, difficult to perform, and is not currently employed in clinical practice. The contribution offered by this data-processing system is emphasized.

Analog-Digital Conversion↗
PubMedDate not supplied

A frequency-time domain signal processing system.

A digital signal processing system for time series analysis with two modes of usage--the first a rapid, hands-on exploratory method, and the second an automatic, printed, labeled graphic output method--is described. The system utilizes a Time Data 1923C system with integral PDP-11 minicomputer, and a console. Major error problems have been contained and a large-volume graphic analysis capability has been developed. Applications include (a) transpulmonary pressure-pulse relationships, (b) elucidation of the multiphasic nature of pulmonary-vein/left-atrial-pressure pulse phenomena, (c) suggestive value of transfer function phenomena as a tool to demonstrate the effect of various loading and ischemic phenomena on the left ventricle, and (d) teaching-demonstration of the techniques of digital signal processing.

Analog-Digital Conversion↗
PubMed1980

Long-term ambulatory physiological surveillance equiment (LAPSE).

A system is described for the acquisition of physiological data for up to 24-hour periods in the ambulant subject free to undertake his usual daily activities. ECG and trunk acceleration signals are recorded on a small analogue magnetic tape recorder along with a stable time-reference. The standard C120 tape cassette used in the recorder is replayed at 60 times the recording speed and the recovered data automatically processed to yield outputs which describe the instantaneous heart rate response of the subject to particular activity. The system is evaluated and the potential indicated by examples of clinical application.

Activities of Daily Living↗
PubMed1978

A method for continuous electrocardiodynamic monitoring.

A new method is presented for the monitoring of cardiac time intervals, e.g. in clinical and industrial work investigation. The methods yields 'on-line' the electrocardiodynamic time profile during rest as well as effort, and has applications in health care, sports and occupational medicine. By means of analog processing of an electrocardiographic signal, ear densitogram and beat-by-beat display of the measured cardiac time intervals as amplitude-modulated pulses, an 'electrocardiodynamic time profile' is obtained. In order to estimate the accuracy and the limitations of the method, a comparison with computerized methods was performed. In an ergonomic experiment carried out by a Romanian-Swedish research team, analog and digital methods for the detection of cardiac time intervals showed good agreement.

Adolescent↗
PubMed1995

[Analysis of the human wrist motion in three dimensions using a video-digitizer].

We report the results of a new assessment system (using a Video-digitizer and non-contact type transducer) in order to clarify the three-dimensional human wrist motion. The results of basic experimental studies conducted prior to this clinical assessment indicated that this new system was an extremely reliable and useful to measure three-dimensional motion. The results of the wrist motion in normal individuals showed supination at radial flexion movement, pronation in ulnar flexion movement, and pronation in the dorso-ulnar part of rotational movement. The comparative results of human wrist motion in pathological conditions suggested that an involvement of the distal radio-ulnar joint was primarily responsible for impairment in the rotational movement of the human wrist.

Adult↗
PubMed1995

[A computerized endurance test: efficacy of pelvic floor rehabilitation treatment in patients with stress incontinence].

In the present study the authors wanted to transfer rigorous methods of study, already in use in other sectors (sports, medicine, isokinetic work, etc.) of the validity of interventions made and their effectiveness, into an "emerging" field, that of perineal rehabilitation. 15 female patients, aged between 35 and 45, affected by stress incontinence underwent a baseline clinico-instrumental evaluation of the perineal floor including a computerized test of endurance. The patients then embarked upon a standardized rehabilitative perineal training lasting a month and at the end underwent an identical evaluation as that performed at the outset. Statistical analysis of the results obtained showed an objective improvement in the parameters considered (endovaginal pressure and its variations during a series of intermittent static contractions) quantitatively supporting clinical evidence.

Adult↗
PubMed1995

[A neurophysiological assessment of the effect of trimetidon on brain function in the cat].

Stimulation of the cat brain mesencephalic RF augmented the high-frequency activity in control animals and failed to do so after 4-oxopyrimidine administration. These and some other EEG changes suggest presence of an anxiolytic component in the trimethidone, the latter thus being similar by its effect to 1,4-benzodiazepines and endogenous pyrimidines.

Analog-Digital Conversion↗