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On examine, dans le présent Digest, l'environnement acoustique d'un bureau sans cloisons, les problèmes qui se posent, et les éléments permettant d'obtenir des résultats acceptables. On exposera enfin un processus d'étude visant à déterminer, au stade de la planification, la situation en un point quelconque d'un bureau sans cloisons.

Linear delta modulation systems use a fixed step size for the 'staircase' approximation of the input signal. Small values of the step size introduce slope overload distortion during bursts of large signal slope. With large values of step size input signals of low amplitude were quantized very coarsely. This results in an inadequate dynamic range. To increase the dynamic range, the step size must be controlled from the time-varying slope characteristic of the input signal.

This Digest examines the acoustical environment of an open office plan, and discusses its problems and the elements that can be utilised to obtain acceptable results. A design procedure follows that allows the condition at any point within an open office to be determined at the planning stage.

L'auteur expose les principes fondamentaux de conception des salles, de la salle de classe à la salle de concert, dont la fonction principale est de favoriser l'efficacité de la communication entre un orateur ou un artiste et son auditoire., Digeste de la construction au Canada, CBD-92F

The paper deals with different ways to discriminate audible tones and speech on a telephone line. Comparing the amplitudes and measuring the zero-crossing distances of successive half periods turn out to be suitable. A series of measurements has been made to compare the two methods. The influence of tolerance, of analog band-limitation, and of the amplitude of superposed speech on the recognition of audible tones is examined. The results show that the evaluation of zero- crossing distances is the most appropriate method.

Basic design principles are given for rooms, ranging from classrooms to concert halls, whose chief function is effective communication from a source (a speaker or performer) to a group of listeners.

A stereo tape was prepared using three talkers separated in 30 degree azimuth steps. Nine ways of connecting the two channels to the two ears were devised, and administered to normal ears and to monaurally defective individuals. Four principles of binaural interaction were enunciated: The Principle of Binaural Gain, the Principle of Redundancy, the Principle of Blurring, and the Principle of Degradation. These principles consider the advantage of a second neural channel, a second 'look' at the stimulus with the same ear, confounding results from receiving information in one ear from noncongruent points in space, and the disadvantage of mixing signals from a normal ear and one in which signals are garbled as a result of a pathological condition. In any one person, speech intelligibility will be the algebraic resultant of whatever principles are operating at the moment.