Frequency modulated oscillator

Claim 1

A FREQUENCY MODULATED OSCILLATOR WHOSE CENTER FREQUENCY MAY BE VARIED IN RESPONSE TO AN ERROR SIGNAL COMPRISING A VOLTAGE REPONSIVE MULTIVIBRATOR CONSTITUTED BY A PAIR OF CROSS-COUPLED TRANSISTORS, MEANS RESPONSIVE TO A MODULAITING SIGNAL TO MODULATE THE OUTPUT OF THE SAID MULTIVIBRATOR BY VARYING THE RATE OF CHANGES OF THE RELATIVE POTENTIALS OF THE RESPECTIVE EMITTER ELEMENTS OF THE SAID PAIR OF TRANSISTORS THEREBY CHANGING THE RATE OF CHANGE OF THE EMITTER-TO-BASE VOLTAGE OF EACH OF SAID PAIR OF TRANSISTORS, MEANS FOR LIMITING THE COLLECTOR ELEMENT OF EACH OF SAID TRANSISTOR TO PREDETERMINED MAXIMUM AND MINIMUM RELATIVE POTENTIALS EACH CORRESPONDING TO A DIFFERENT ONE OF THE CONDUCTING AND NON-CONDUCTING CONDITIONS OF EACH OF SAID TRANSISTORS, AND MEANS RESPONSIVE TO SAID ERROR SIGNAL FOR BIASING SAID LIMITING MEANS TO CHANGES THE CENTER FREQUENCY OF SAIMULTIVIBRATOR BY CHANGING THE RELATIVE POTENTIALS OF THE RESPECTIVE COLLECTOR ELEMENTS THEREBY CHANGING THE EMITTER-TO-BASE BIAS OF EACH OF SAID PAIR OF TRANSISTOR.