GB1130314A - Improvements in vibrating string gyroscopes - Google Patents

Abstract

1,130,314. Vibrating string gyros. CSF COMPAGNIE GENERALE DE TELEGRAPHIE SANS FIL. Feb.14, 1966, No.6442/66. Headings G1C and G1N. A system for measuring an angular velocity component about an axis Oz comprises a frame 2, a conductive vibrating string stitched on the frame along the axis Oz, the string being vibrated by supplying to it an alternating current of a frequency f 1 which is one of the resonant frequencies of the string e. g. that corresponding to one wavelength as shown, and by the provision of a D.C. inductor 3 providing a magnetic field along the axis Oy, an A. C. inductor 4 providing an alternating magnetic field along the axis Ox of a frequency f 2 less than f 1 whereby an amplitude modulated signal is induced in the string having a modulation depth which is a function of the sine of the angle of inclination of the plane of vibration of the string to the reference plane xOz caused by the angular velocity component to be measured, and modulation depth measuring means connected across the string, this means comprising a reactance circuit 6, through the two branches of which flow currents i 12 and i 21 corresponding respectively to the components f 1 +f 2 and f 1 -f 2 of the amplitude modulation so that the current flowing through an ammeter 7 connected in series with the circuit 6, deviates in proportion with the rotation of the plane of vibration of the string about the axis Oz. The A. C. current of frequency f 1 is derived from a source which supplies the energy necessary to keep the string in oscillation, e.g. an amplifier with feedback.