Doppler effect compensation

Claim 1

A RADIO STATION ADAPTED TO COMPENSATE AUTOMATICALLY FOR DOPPLER FREQUENCY SHIFT IN TRANSMISSION FROM A REMOTE TRANSMITTING APPARATUS, MOVING RELATIVELY TO THE SAID STATION, OF COMMUNICATIONS SIGNALS RECEIVED AT THE SAID STATION FROM THE SAID REMOTE TRANSMITTING APPARATUS, COMPRISING: MEANS FOR RECEIVING A PILOT SIGNAL TRANSMITTED AT A PREDETERMINED KNOWN FIRST FREQUENCY FROM THE SAID REMOTE TRANSMITTING APPARATUS, THE SAID PILOT SIGNAL BEING SHIFTED BY THE DOPLLER EFFECT DURING TRANSMISSION SO THAT UPON ITS ARRIVAL AT THE SAID STATION IT HAS A SECOND FREQUENCY DIFFERENT FROM THE SAID FIRST FREQUENCY AND FOR DERIVING FROM THE SAID PILOT SIGNAL AS RECEIVED AT THE SAID STAT ION AT THE SAID SECOND FREQUENCY A CONTROL SIGNAL REPRESENTATIVE OF THE ALGEBRAIC DIFFERENCE BETWEEN THE SAID KNOWN FIRST FREQUENCY AND THE SAID SECOND FREQUENCY; COMUNICATION SIGNAL RECEIVING MEANS TURNED TO RECEIVE BAND OF FREQUENCIES DIFFERENT FROM THE SAID FIRST FREQUENCY AND THE SAID SECOND FREQUENCY AND HAVING A CENTER FREQUENCY, AND TUNABLE BY APPLICATION OF A CONTROL SIGNAL TO DISPLACE, IN FREQUENCY, THE SAID BAND OF FREQUENCIES; MEANS FOR APPLYING THE SAID CONTROL SIGNAL TO THE SAID COMMUNICATION SIGNAL RECEIVING MEANS TO TUNE THAT MEANS TO DISPLACE THE SAID BAND OF FREQUENCIES BY AN AMOUNT BEARING THE SAME RATIO TO THE CENTER FREQUENCY OF THE UNDISPLACED SAID BAND FIRST AND SECOND FREQUENCIES TO THE SAID FIRST FREQUENCY, AND OF THE SAME ALGEBRAIC SIGN.