Automatic electronic frequency control

Claim 1

IN AN AUTOMATIC FREQUENCY CONTROLLER FOR A PULSED ENERGY SYSTEM HAVING A RADAR TRANSMITTER OF PULSED A.-C. ENERGY, A LOCAL OSCILLATOR, AN INTERMEDIATE FREQUENCY RECEIVER RESPONSE TO SAID TRANSMITTED ENERGY AND SAID LOCAL OSCILLATOR, AND A MICROWAVE MIXER RESPONSIVE TO BOTH SAID PULSED A.-C. ENERGY AND THE OUTPUT OF SAID LOCAL OSCILLATOR FOR PROVIDING AN INTERMEDIATE FREQUENCY SIGNAL, THE COMBINATION COMPRISING A FREQUENCY DISCRIMINATOR FOR PROVIDING A D.-C. SIGNAL HAVING A SENSE CORRESPONDING TO THE FREQUENCY DIFFERENCE BETWEEN SAID INTERMEDIATE FREQUENCY SIGNAL AND A SELECTED REFERENCE FREQUENCY AND COMPRISING AND L-C BRIDGE RESPONSIVE TO SAID MIXER, AND SUMMING RESPONSIVELY COUPLED TO SAID L-C BRIDGE HAVING FIRST AND SECOND OPPOSITELY-POLED UNIDIRECTIONALLY CONDUCTIVE SUMMING IMPEDANCE BRANCHES; MEANS FOR LIMITING THE RESPONSE OF SAID DISCRIMINATOR TO HARMONICS OF SAID SELECTED REFERENCE FREQUENCY AND COMPRISING A RESISTIVE IMPEDANCE CONNECTED ACROSS THE INPUT OF SAID L-C BRIDGE AND BI-POLAR SIGNAL LIMITING MEANS COUPLED ACROSS THE OUTPUT OF SAID SIGNAL SUMMING MEANS OF SAID FREQUENCY DISCRIMINATOR; AND BI-POLAR PULSE-INTEGRATING MEANS RESPONSIVE TO THE LIMITED OUTPUT OF SAID DISCRIMINATOR FOR PROVIDING A D.-C. CONTROL SIGNAL FOR FREQUENCY CONTROL OF ONE OF SAID LOCAL OSCILLATOR AND RADAR TRANSMITTER, AND COMPRISING AN INPUT TERMINAL COUPLED TO SAID DISCRIMINATOR, A FIRST AND SECOND SERIES-INTERCONNECTED CAPACITOR CONNECTED ACROSS A D.-C. VOLTAGE SOURCE, THE INTERCONNECTION OF SAID CAPACITORS FORMING AN OUTPUT TERMINAL, A FIRST AND SECOND MUTUALLY COMPLEMENTARY SWITCHING MEANS HAVING CONTROL TERMINALS COMMONLY COUPLED TO SAID INPUT TERMINAL, AND ARRANGED FOR DISCHARGED A SELECTED ONE OF SAID CAPACITORS CORRESPONDING TO A PRESELECTED POLARITY OF A PULSED INPUT APPLIED TO SAID INPUT TERMINAL.