PTTI applications at Hydro-Quebec

As a power utility, Hydro-Quebec used the PTTI techniques. The time dissemination system in the Hydro-Quebec Network (11th PTTI) is now installed in several points. A portable clock was built using a rubidium standard and associated circuitry which are necessary for the measurements. The apparatus and the experimental results obtained are described. The use of GOES synchronized clocks for making precise voltage angle measurement on the Hydro-Quebec Network is discussed. Some modifications were made on a commercial unit. Applications and results are presented

Time transfer by IRIG-B time code via dedicated telephone link

Measurements were made of the stability of time transfer by the IRIG-B code over a dedicated telephone link on a microwave system. The short and long term Allan Variance was measured on both types of microwave system, one of which is synchronized, the other having free local oscillators. The results promise a time transfer accuracy of 10 microns. The paper also describes a prototype slave clock designed to detect interference in the IRIG-B code to ensure local time is kept during such interference

Études de filtres isotopiques pour les masers au rubidium

The filtering of a rubidium 85 lamp by a filter containing rubidium 87 has been studied ; the influence of the nature and of the pressure of the buffer gas on the efficiency of the filter is shown. It is shown in particular that helium used as a buffer gas makes possible the construction of efficient filters. A short description of the Fabry-Pérot interferometer used in these studies is given. These studies have made possible the realization of a Rb 85 maser.Le filtrage isotopique d'une lampe au rubidium 85, à l'aide de l'isotope 87, a été étudié ; en particulier, on a fait ressortir l'influence sur le filtrage de la nature et de la pression du gaz tampon contenu dans le filtre. On montre en outre qu'il est possible de réaliser un filtrage efficace en utilisant de l'hélium comme gaz tampon. Ces études ont été faites à l'aide d'un spectromètre Fabry- Pérot dont une description sommaire est faite. Ces études ont de plus permis la réalisation d'un maser Rb 85