抄録
For the elimination of an extra transducer which picks up voltage proportional to the velocity of mechanical vibration for feedback oscillation, a new method to insert a network between the power amplifier and the main transducer is deviced. Three types of the network are proposed and theoretical formulas are derived. Behaviour of the motional feedback oscillators are generally discussed and the ability of automatic frequency tracking and the relation between the amplitude and mechanical load are made clear by graphical representation for the purpose of design. For the experiment, two sets of 50W class oscillator on our principle were built. Experiments proved that the frequency tracking is fairly good even when the transducer has subsidiary resonances, and that the velocity amplitude of the transducer is nearly constant in spite of the variation of the acoustical load if the gain-amplitude character of the amplifier is appropriately designed.
