Renseignements généraux

Nº de série

30

Nº de partie

1

Nombre total de parties

23

Ou

S/O

Brevets

S/O

Description générale

metal casing/ synthetic controls on casing top/ metal tape spools and parts/ synthetic tape assembly cover on casing top/ synthetic parts

Dimensions

Remarque : Cette information reflète la taille générale pour l’entreposage et ne représente pas nécessairement les véritables dimensions de l’objet.

Longueur

97,5 cm

Largeur

41,0 cm

Hauteur

29,2 cm

Épaisseur

S/O

Poids

S/O

Diamètre

S/O

Volume

S/O

Lexique

Groupe

Technologie informatique

Catégorie

Dispositifs analogiques

Sous-catégorie

S/O

Fabricant

Ou

Noratom

Pays

Norvège

État/province

Inconnu

Ville

Oslo

Contexte

Pays

Canada

État/province

Ontario

Période

circa 1966 +

Canada

An example of a Norwegian made analogue computer used for scientific purposes at a Canadian university. Information provided by Dr. Don Moorcroft 2004/01/28 (see worksheet in Supp. Info.): The Noratom ISAC (Instrument for Statistical Analog Computations) was purchased in 1966 for $5,468.00. It was probably bought by Dr. Peter Forsyth, who was then head of the Physics Department of the University of Western Ontario and also head of the group of people using radio and radar techniques in the study of the Earth's ionosphere. Dr. Moorcroft's general area of interest has been in the study of small-scale structure in the ionosphere. This has usually been connected with the ionospheric E-region and the auroral zone, but at times has spread to other phenomena and/or at other heights. In the late 1960's there was considerable interest in the nature of the irregularities responsible for the scintillation of signals received on the ground from transmitters aboard artificial satellites, a direct outgrowth of the study of radio stare scintillations, which happened to be the topic of Dr. Moorcroft's Ph.D. thesis. One of the main reasons for getting this analogue computer was to analyse observations of these scintillations. The idea was that you put out three antennas in a triangle, with separations of a few hundred metres. The irregularities refract the radio waves from the satellite, and produce a varying pattern of phase and amplitude fluctuations which drifts across the receivers as the satellite moves overhead. The phase and/or amplitude fluctuations were recorded at each of the three stations and by measuring the cross-correlation between the signals from the different stations it was possible to determine the shape of the pattern on the ground, and hence, by suitable modelling, some of the characteristics of the irregularities in the ionosphere, both their height and shape.

Fonction

An analogue computer is a programmable machine that processes data represented by directly measurable quantities (such as voltages) which vary continuously. This computer was designed primarily for practical applications of statistical methods to problems in automatic control, especially for determining system transfer function of industrial processes.

Technique

An example of an analogue computer of the1950's. Information provided by Dr. Don Moorcroft 2004/01/28 (see worksheet in Supp. Info.): The reason that UWO purchased this analogue system, rather than using a digital computer relates to the state of computing at the time. In 1966, the computers being used (outside of the military and defence establishments, perhaps) were central mainframe computers. In order to use a computer to analyse these data at that time it was necessary to make plots of the signals from each of the receivers, have someone scale them meticulously by hand, and then enter that information onto punched cards which could then be submitted as input to a computer program. It wasn't until 1970, with the production of the first PDP-11 computer by the Digital Equipment Corporation (DEC), that computers within the reach of individual research groups were widely available, and even then they were relatively expensive, certainly compared to the ISAC. The ISAC was ideally suited to the analysis of the spaced receiver data, since it had three channels, one for each of the receiver amplitudes. A UWO masters student, Kathy Arima, completed her degree on a project which used the ISAC. Her thesis, "Correlation Analysis of Satellite Amplitude Scintillations", was submitted in October, 1969 (see also Ref. 3).

Notes sur la région

Inconnu

Détails

Marques

plate on back reads 'NORATOM AS/ TYPE 5003 SER. NO. 30/ 115V 60 HZ A'/ red and black lettering on top reads 'NORATOM/ STATISTICAL ANALOGUE COMPUTER/ TYPE SINTEF/ NOR 5003' / black lettering for control functions/ labels reading 'THE UNIVERSITY OF WESTERN/ ONTARIO/ 0001205' and 'the university of/ western ontario'

Manque

XY recorder component

Fini

casing painted glossy dark green with glossy light green top/ black and red synthetic controls on casing top/ plated tape spools and colourless transparent tape assembly cover on casing top/ metallic and plated parts/ multicoloured synthetic parts

Décoration

S/O