Detection of remote phase modulation of variable frequency carrier

Claim 1

IN A SYSTEM FOR PHASE DETECTION AT A RECEIVING STATION OF INTELLIGENCE PHAE MODULATING, AT A STATION REMOTE FROM A LOCAL STATION, A FIRST CARRIER OF VARIABLE FREQUENCY GENERATED AT THE LOCAL STATION AND TRANSMITTED BY TRANSMITTING MEANS TO THE REMOTE STATION, THE REMOTE STATION INCLUDING A TRANSMITTER FOR GENERATING AND BROADCASTING A SECOND CARRIER MODULATED BY SAID PHASE MODULATED FIRST CARRIER AS A SUBCARRIER, AND THE RECEIVING STATION INCLUDING MEANS FOR RECEIVING SAID SUBCARRIER AND A PHASE DETECTOR FOR MEASURING THE PHASE DIFFERENCE BETWEEN THE RECEIVED SUBCARRIER AND A REFERENCE SIGNAL HEREINAFTER DEFINED, THE PROVISION OF TIME DELAY MEANS FOR RECEIVING AS AN INPUT SIGNAL SAID FIRST CARRIER AS GENERATED AT THE LOCAL STATION AND FOR PRODUCING THEREFROM AN OUTPUT SIGNAL CONSTITUTING SAID REFERENCE SIGNAL AND CORRESPONDING TO SAID INPUT SIGNAL BUT DELAYED THREBEHIND BY A TIME EQUAL TO THE TRANSIT TIMES FROM THE LOCAL STATION TO THE REMOTE STATION AND THENCE TO THE RECEIVING STATION MINUS THE TRANSIT TIME FROM THE LOCAL STATION TO THE RECEIVING STATION.