Intermediate frequency preamplifier circuit

Claim 1

A PREMPLIFIER CIRCUIT FOR USE IN A RADAR RECEIVER EMPLOYING A LOGARITHMIC POSTAMPLIFIER CIRCUIT COMPRISING: A FIRST TRIODE VACUUM TUBE HAVING ANODE, GRID, AND CATHODE ELECTRODES, SAID GRID ELECTRODE BEING INDUCTIVELY COUPLED TO A MICROWAVE MIXER STAGE FOR RECEIVING RADAR SIGNAL INFORMATION THEREFROM, AND SAID CATHODE ELECTRODE POTENTIAL; MEANS TO GROUND POTENTIAL; FIRST ADJUSTABLE IMPEDANCE MATCHING MEANS HAVING INPUT MEANS COUPLED TO SAID ANODE ELECTRODE OF SAID FIRST TUBE, HAVING FEEDBACK MEANS COUPLED TO SAID GRID ELECTRODE OF SAID FIRST TUBE FOR NEUTRALIZING THE GRID-TO-PLATE CAPACITANCE THEREOF, AND HAVING OUTPUT MEANS FOR PROVIDING SAID RADAR SIGNAL INFORMATION THEREAT; A SECOND TRIODE VACUUM TUBE HAVING ANODE, GRID, AND CATHODE ELECTRODES, SAID GRID ELECTRODE BEING CAPACITIVELY COUPLED TO GROUND POTENTIAL AND SAID ANODE ELECTRODE BEING INDUCTIVELY COUPLED TO SAID POSTMAPLIFIER CIRCUIT FOR PROVIDING SAID RADAR SIGNAL INFORMATION THERETO; A FIRST RELATIVELY LOSSLESS ELECTRICAL COUPLING MEANS HAVING ONE END THEREOF COUPLED TO SAID OUTPUT MEANS OF SAID FIRST ADJUSTABLE IMPEDANCE MATCHING MEANS AND HAVING THE OTHER END CAPACITIVELY COUPLED TO SAID CATHODE ELECTRODE OF SAID SECOND TUBE, FOR COUPLING SAID RADAR SIGNAL INFORMATION FROM SAID FIRST TUBE TO SAID SECOND TUBE; SECOND ADJUSTABLE IMPEDANCE MATCHING MEANS COUPLED BETWEEN SAID CATHODE ELECTRODE OF SAID SECOND TUBE AND GROUND POTENTIAL IN ORDER TO TERMINATE SAID OTHER END OF SAID FIRST COUPLING IN THE PROPER IMPEDANCE; AND A SECOND COUPLING MEANS HAVING ONE END THEREOF CAPACITIVELY COUPLED TO SAID CATHODE ELECTRODE OF SAID SECOND TUBE TO PROVIDE A SAMPLE OF SAID RADAR SIGNAL INFORMATION TO SUBSEQUENT CIRCUITRY.