Diode logarithmic encoder

Claim 1

APPARATUS FOR LOGARITHMETICALLY CODING A SIGNAL WAVE WHICH COMPRISES MEANS FOR DERIVING, AT CONSECUTIVE SAMPLING INSTANTS, SAMPLES OF SUCCESSIVE AMPLITUDES OF THE SIGNAL WAVE, A STORAGE CONDENSER, A LOW RESISTANCE PATH EXTENDING FROM SAID SAMPLING MEANS TO SAID CONDENSER, MEANS FOR SUBSTANTIALLY INSTANTANEOUSLY CHARGING SAID CONDENSER WITH SAID SUCCESSIVE AMPLITUDE SAMPLES, A DISCHARGE PATH, OF SUBSTANTIALLY HIGHER RESISTANCE THAN THAT OF SAID LOW RESISTANCE PATH, EXTENDING FROM SAID CONDENSER TO A FIXED POTENTIAL POINT AND INCLUDING AS AN ELEMENT A VOLTAGE-CONTROLLED DIODE CHARACTERIZED BY TWO DISTINCT STATES OF CONDUCTION, SAID DIODE BEING THUS DRIVEN TO ITS SECOND STATE WHEN THE CONDENSER IS CHARGED AND BEING RETURNED TO ITS FIRST STATE WHEN THE CONDENSER IS DISCHARGED, SAID CONDENSER AND SAID DISCHARGE PATH BEING PROPORTIONED TO PROVIDE A DISCHARGE TIME FOR SAID CONDENSER LESS THAN THE INTERSAMPLE INTERVAL, A CONSTANT FREQUENCY OSCILLATOR OF WHICH THE ACTIVE ELEMENT IS A SECOND VOLTAGE-CONTROLLED DIODE HAVING A NEGATIVE RESISTANCE CHARACTERISTIC AND A THRESHOLD OF OPERATION, A COUPLING PATH EXTENDING FROM SAID FIRST DIODE TO SAID DIODE, THE CHARACTERISTIC OF SAID SECOND DIODE BEING SO COORDINATED WITH THE CHARACTERISTIC OF SAID FIRST DIODE THAT PASSAGE OF SAID FIRST DIODE FROM ITS FIRST STATE TO ITS SECOND STATE DRIVES SAID SECOND DIODE FROM BELOW ITS THRESHOLD OF OPERATION TO ABOVE ITS THRESHOLD OF OPERATION, AND PASAGE OF SAID FIRST DIODE FROM ITS SECOND STATE TO ITS FIRST STATE DRIVES SAID SECOND DIODE FROM ABOVE ITS THRESHOLD OF OPERATION TO BELOW ITS THRESHOLD OF OPERATION, WHEREBY SUCCESSIVE DISCHARGES OF SAID CONDENSER THROUGH SAID FIRST DIODE CAUSE SUCCESSIVE OSCILLATION TRAINS OF SAID OSCILLATOR, AND WHEREBY THE NUMBERS OF FULL CYCLES IN THE SUCCESSIVE TRAINS ARE PROPORTIONAL TO THE LOGARITHMS OF THE AMPLITUDES OF THE SIGNAL WAVE AT THE SUCCESSIVE SAMPLING INSTANTS.