System for linearly tuning a microwave oscillator

In a generator of microwaves of variable frequency provided with a resonant cavity and a tuning element in said cavity, said tuning element being linearly displaceable between two terminal positions corresponding to respective limiting frequencies f.sub.1 and f.sub.2,

• the combination therewith of:
• a rotatable crankshaft;
• a mechanical linkage coupling said crankshaft with said tuning element, said linkage including a pitman with a first extremity fulcrumed on said crankshaft and a second extremity positively connected with said tuning element via a pivotal joint, said crankshaft having an eccentricity e, said pitman having an effective length p measured between the pivotal axes of said extremities, said second extremity being substantially linearly guided between a first dead-center position farther from the axis of said crankshaft and a second dead-center position closer to said axis respectively coinciding with said terminal positions of said tuning element;
• drive means coupled with said crankshaft for rotating same about said axis;
• and
• position-sensing means coupled with said crankshaft for emitting an output signal varying as a sinusoidal function of the angle of rotation of the crankshaft from a predetermined reference position;
• the length p being related to the eccentricity e by the expression ##EQU6## where q is the distance of travel of said second extremity between said first dead-center position and an intermediate position thereof in which said frequency has a mean value of (f.sub.1 +f.sub.2)/2 whereby said frequency varies as a sinusoidal function of said angle of rotation and is proportional to said output signal.