PROCEDE ET DISPOSITIF POUR ADAPTER AUTOMATIQUEMENT L'INDEPENDANCE D'UN TRANSDUCTEUR ELECTRO-ACOUSTIQUE

摘要

The output of an oscillator (1) is connected through a coupling transformer (2) to a transducer (3) whose equivalent circuit comprises an inductor (LM) equivalent to the mass of material. A capacitance (CM) is equivalent to the material rigidity and a resistor (RM) corresponds to the mechanical losses and radiated energy. A second capacitor (CO) corresponds to the dielectric losses and is the significant component. An inductor (L) is placed in parallel with the transducer and is in parallel with a variable inductor (LV) in series with back to back thyristors (Th1,2). Toroidal detectors (5,7) sense voltages proportional to phase of the respective currents (IE,IL) w.r.t. the voltage (VL) from a divider circuit. A control circuit (4) containing a servo loop compares the phase differences between the voltage and generator current (IE). The error signal controls the thyristor to maintain the phase difference close to zero by modifying the current in the variable inductor.