A frequency-time domain signal processing system.

P V Moulder; W Rank; G R Daicoff

PubMed · 7366514

A frequency-time domain signal processing system.

Abstract

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.

Explore related subjects

Analog-Digital Conversion Biomedical Engineering Blood Pressure Computers Data Display Heart Pulse Venous Pressure Journal Article

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

P V Moulder, W Rank, G R Daicoff. A frequency-time domain signal processing system.. https://pubmed.ncbi.nlm.nih.gov/7366514/

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed1997

Computer-based desktop system for surgical videotape editing.

BACKGROUND: The educational role of surgical video presentations should be optimized by linking surgical images to graphic evaluation of indications, techniques, and results. We describe a PC-based video production system for personal editing of surgical tapes, according to the objectives of each presentation. METHODS: The hardware requirement is a personal computer (100 MHz processor, 1-Gb hard disk, 16 Mb RAM) with a PC-to-TV/video transfer card plugged into a slot. Computer-generated numerical data, texts, and graphics are transformed into analog signals displayed on TV/video. A Genlock interface (a special interface card) synchronizes digital and analog signals, to overlay surgical images to electronic illustrations. The presentation is stored as digital information or recorded on a tape. RESULTS: The proliferation of multimedia tools is leading us to adapt presentations to the objectives of lectures and to integrate conceptual analyses with dynamic image-based information. We describe a system that handles both digital and analog signals, production being recorded on a tape. Movies may be managed in a digital environment, with either an "on-line" or "off-line" approach. System requirements are high, but handling a single device optimizes editing without incurring such complexity that management becomes impractical to surgeons. CONCLUSIONS: Our experience suggests that computerized editing allows linking surgical scientific and didactic messages on a single communication medium, either a videotape or a CD-ROM.

Analog-Digital Conversion↗

PubMed1997

Left ventricular pressure and volume data acquisition and analysis using LabVIEW.

To automate analysis of left ventricular pressure-volume data, we used LabVIEW to create applications that digitize and display data recorded from conductance and manometric catheters. Applications separate data into cardiac cycles, calculate parallel conductance, and calculate indices of left ventricular function, including end-systolic elastance, preload-recruitable stroke work, stroke volume, ejection fraction, stroke work, maximum and minimum derivative of ventricular pressure, heart rate, indices of relaxation, peak filling rate, and ventricular chamber stiffness. Pressure-volume loops can be graphically displayed. These analyses are exported to a text-file. These applications have simplified and automated the process of evaluating ventricular function.

Analog-Digital Conversion↗

PubMed1997

Simultaneous monitoring of head-to-cervix forces, intrauterine pressure and cervical dilatation during labour.

In many westernized countries, the caesarean section role has now reached 15% or more, most commonly because of slow progress in labour. In order for labour to result in a vaginal delivery, the uterine cervix must dilate to allow the foetus to travel through the birth canal. This process is driven by uterine contractions, but the mechanisms by which the contractions result in cervical dilatation are still far from clear. The force exerted by the presenting part (foetal head) on the cervical tissue during contractions (head-to-cervix force, HCF) has been shown to be the variable with the best correlation with cervical dilatation. Unfortunately, the mechanism by which these two variables are related is still poorly understood. In order to investigate the relationship between head-to-cervix force, intrauterine pressure (IUP) and cervical dilatation, we have developed a system for their simultaneous and continuous monitoring during labour. The HCF is measured by using a novel intrauterine probe which is slipped alongside the foetal head so as to lie sandwiched between the latter and the cervix. The probe is fitted with six specially designed miniature force sensors, spaced 1.8 cm apart, which respond linearly and approximate the behaviour of load cells. They are interfaced with a PC by circuitry that allows auto-zeroing and drift compensation. The system enables simultaneous acquisition of intrauterine pressure and foetal heart rate (measured using a Sonicaid Meridian foetal monitor) via a serial link, together with continuous cervical dilatation measured by a caliper-like device applied to the cervix. Some preliminary data are presented, which suggest that the system can be used to investigate the role played by head-to-cervix force and intrauterine pressure in the cervix dilatation process.

Analog-Digital Conversion↗