Societe De Fabrication D'instruments De Mesure (s.f.i.m.)

Societe De Fabrication D'instruments De Mesure

Charlie Pelletier

Jean-Thierry Audren

The invention relates to a signal generator with programmable variable frequency and comprises a reference oscillator, a first frequency divider receiving the signal emitted by the reference oscillator and delivering an instantaneous frequency signal (FS). A control chain for said first frequency divider comprises a second frequency divider and a first programmable integrator system, which controls the first frequency divider. A control chain for the second frequency divider comprises a second integrator system receiving the output signal (FS). This signal has an instantaneous frequency of the polynomial form ##EQU1##

Signal generator with programmable variable frequency

An electrostatic motor is constituted by a capacitor (10) having relatively movable electrodes (11, 12) separated by a variable gap (13). The control circuit includes a DC source (60) which is servo-controlled to current measurement means (20) and integrator means (30) for calculating the charge on the capacitor plates and for maintaining said charge constant (Q.sub.0). By applying servo control to keep the charge constant, the force on the plates is independent of the variable value of the gap (14). The charge is preferably on/off switched with a pulse width modulation ratio that is a function of the force which is to be applied.

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Massy, France

Charlie Pelletier