F. m. range finder with doppler error compensation

Claim 1

A FREQUENCY MODULATED CONTINUOUS WAVE RADIO RANGE FINDER COMPRISING, MEANS FOR PROPAGATING A BEAM OF FREQUENCY MODULATED CARRIER WAVES HAVING A PLURALITY OF UPPER AND LOWER SIDEBANDS TOWARD A TARGET WHICH HAS A RELATIVE VELOCITY WITH RESPECT TO THE PROPAGATING MEANS AND FOR RECEIVING THE BACK SCATTERED RADIATION FROM THE TARGET, MEANS FOR DISPLACING THE CARRIER WAVE FREQUENCY BY AN AMOUNT CORRESPONDING TO THE VELOCITY BETWEEN THE PROPAGATING MEANS AND THE TARGET ALONG THE BEAM OF RADIATED ENERGY, MEANS INCLUDING A MIXER RESPONSIVE TO THE DISPLACED CARRIER WAVE AND TO THE RECEIVED BACK SCATTERED RADIATION FROM THE TARGET FOR CAUSING CORRESPONDING UPPER AND LOWER SIDEBANDS OF THE RECEIVED BACK SCATTERED RADIATION TO OVERLIE EACH OTHER, FILTER MEANS RESPONSIVE TO THE OUTPUT FROM SAID MEANS INCLUDING THE MIXER FOR SELECTING AND DOUBLING THE FREQUENCY OF ONE PAIR OF SAID OVERLYING CORRESPONDING SIDEBANDS, MEANS FOR MULTIPLYING THE MODULATING FREQUENCY SO THAT IT EQUALS THE DOUBLED FREQUENCY, AND MEANS FOR COMPARING THE PHASES OF THE DOUBLED FREQUENCY AND THE MULTIPLIED MODULATING FREQUENCY AND FOR PROVIDING A SIGNAL WHICH CORRESPONDS TO THE PHASE DIFFERENCE BETWEEN SAID SIGNALS BEING PHASE COMPARED.