Amplitude comparator system

Claim 1

A SYSTEM FOR COMPARING THE AMPLITUDE OF AN INPUT VOLTAGE WITH THE AMPLITUDE OF A CYCLICLY VARYING REFERENCE VOLTAGE AND FOR PROVIDING AN OUTPUT LOGIC SIGNAL AT THE INSTANT OF EQUALITY BETWEEN THE AMPLITUDES OF SAID VOLTAGES, COMPRISING THE COMBINATION OF A FIRST COMPARATOR CIRCUIT RESPONSIVE TO SAID INPUT VOLTAGE AND TO SAID REFERENCE VOLTAGE, SAID COMPARATOR CIRCUIT COMPRISING A DIFFERENTIAL AMPLIFIER, A BISTABLE CIRCUIT FOR PROVIDING AN OUTPUT PULSE RESPONSIVE TO THE OUTPUT OF SAID DIFFERENTIAL AMPLIFIER, SAID BISTABLE CIRCUIT REVERSING STATES WHEN THE AMPLITUDE OF SAID REFERENCE VOLTAGE BECOMES EQUAL TO THE AMPLITUDE OF SAID INPUT VOLTAGE, AND A UNIDIRECTIONALLY CONDUCTING ELEMENT COUPLING SAID OUTPUT PULSE TO A CONTROL TERMINAL ON SAID DIFFERENTIAL AMPLIFIER FOR RENDERING INEFFECTIVE THE INPUT CIRCUIT OF SAID DIFFERENTIAL AMPLIFIER WHEREBY THE INPUT IMPEDANCE OF SAID DIFFERENTIAL AMPLIFIER BECOMES VERY HIGH DURING THE ENTIRE TIME OF NONEQUALITY OF THE VOLTAGES TO BE COMPARED; A SECOND COMPARATOR CIRCUIT RESPONSIVE TO SAID REFERENCE VOLTAGE; A LOGIC CIRCUIT RESPONSIVE TO THE OUTPUTS OF SAID FIRST AND SECOND COMPARATOR CIRCUITS FOR PROVIDING A PULSE WAVEFORM, THE DURATION OF EACH PULSE IN SAID WAVEFORM BEING PROPORTIONAL TO THE ABSOLUTE VALUE OF THE AMPLITUDE OF SAID INPUT VOLTAGE; A SIGNAL GENERATOR FOR PROVIDING A SIGNAL OF THE PREDETERMINED FREQUENCY: AND A GATE CIRCUIT AN OUTPUT TERMINAL, SAID GATE CIRCUIT BEING RESPONSIVE TO SAID SIGNAL AND TO SAID PULSE WAVEFORM FOR DELIVERING TO SAID OUTPUT TERMINAL A SERIES OF PULSES, THE NUMBER OF PULSES IN SAID SERIES BEING DIRECTLY PROPORTIONAL TO THE AMPLITUDE OF SAID INPUT VOLTAGE.