Oscillators – With outer casing or housing – With temperature modifier
Patent
1990-04-11
1991-06-18
Grimm, Siegfried H.
Oscillators
With outer casing or housing
With temperature modifier
219210, 310343, H03B 532, H03L 104
Patent
active
050252283
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a piezoelectric resonator oscillator of ultrastable frequency and functioning both at atmospheric pressure and under vacuum.
Piezoelectric resonator oscillators constitute time bases for a large number of instruments. These time bases have to be as accurate as possible. There are many parameters having a bearing on the frequency stability, namely temperature, pressure, vibrations, shocks, age, starting and stopping, etc. Temperature and pressure variations particularly exert considerable influence on the frequency stability of a piezoelectric resonator oscillator.
The oscillators on board satellites must function with a high frequency stability, both at atmospheric pressure before launching and under vacuum when the satellite is in orbit. Moreover, temperature variations do not occur in the same way under vacuum or in the atmosphere because in a vacuum there is no convection.
The materials used in the oscillators intended for functioning both under vacuum and at atmospheric pressure must satisfy a certain number of criteria. They must first conform to the rules of space, especially as regards the condensate ratio and the rate of weight loss. They must also guarantee a low variation of thermal resistance, so as to minimise the temperature variations during the transition from atmospheric pressure to a vacuum, and vice versa.
Ultrastable piezoelectric resonator oscillators of known type are usually inserted in a Dewar vessel, in order to guarantee good thermal insulation relative to the exterior.
The present invention provides a piezoelectric resonator oscillator of ultrastable frequency, the frequency stability performances of which are obtained by means of an assembly making it possible to avoid using a Dewar vessel.
The present invention provides an oscillator of ultrastable frequency functioning at atmospheric pressure and under vacuum, comprising a piezoelectric resonator consisting of a piezoelectric reed encased in a housing composed of a cap and of a base, the resonator being placed inside a thermostatically controlled containment comprising sides limited by a bottom and by at least one cover, characterized in that the thermostatically controlled containment consists of an outer cell possessing a bottom and sides and of an inner cell possessing a bottom and sides, the inner cell being inserted in the outer cell in such a way that their sides are in contact, and in that the bottom of the thermostatically controlled containment has at least the bottom of the outer cell and the bottom of the inner cell.
The inner cell can be screwed into the outer cell.
A soft thermal seal can be inserted between the bottom of the inner cell and the bottom of the outer cell.
The cap of the resonator can be soldered on its entire outer surface to the inside of the inner cell.
The thermostatically controlled containment will be inserted into an intermediate containment, a narrow space being formed between the two containments, so as to minimise convection phenomena when work is being carried out at atmospheric pressure.
The inner surface of the intermediate containment will be bright in order to minimise thermal losses as a result of the radiation of the thermostatically controlled containment.
The invention will be better understood and other advantages will emerge from the following description given in a non-limiting way and accompanied by the single figure which illustrates a sectional view of an ultrastable piezoelectric resonator oscillator according to the invention.
In this figure, the piezoelectric resonator 1 comprises a reed of piezoelectric material 2 held by two conductive posts 3, to which are fastened electric wires 4 making the electrical connection with an oscillator circuit 5.
The piezoelectric reed 2 is encased in a housing consisting of a cap 7 and of a base 8. The resonator 1 is placed inside a thermostatically controlled containment 10 comprising a bottom 15 and sides 14.
As in our figure, the thermostatically controlled containment 10 can consist of two cavities 6, 1
REFERENCES:
patent: 3007023 (1961-10-01), Johnston
patent: 3252109 (1966-05-01), White
patent: 3617692 (1971-11-01), Landis
Debaisieux Andre
Gerard Evelyne
Molle Roger
Compagnie d'Electronique et de Piezo-Electricite D.E.P.E.
Grimm Siegfried H.
LandOfFree
Ultrastable oscillator functioning at atmospheric pressure and u does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Ultrastable oscillator functioning at atmospheric pressure and u, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ultrastable oscillator functioning at atmospheric pressure and u will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-147512