Waveform sampling circuit

Claim 1

A CIRCUIT FOR DRIVING A GRAPHIC RECORDER AT A CONSTANT WRITING RATE TO REPRODUCE A PERIODICALLY RECURRING WAVEFORM, SAID CIRCUIT COMPRISING A SAMPLING GATE HAVING AN INPUT AND AN OUTPUT, MEANS TO APPLY SAID WAVEFORM TO THE INPUT OF SAID SAMPLING GATE, A STRETCHER HAVING AN INPUT AND AN OUTPUT, SAID STRETCHER COMPRISING ANOTHER GATE AND A STORAGE ELEMENT, MEANS CONNECTING THE OUTPUT OF SAID SAMPLING GATE AND THE INPUT OF SAID STRETCHER, FIRST AND SECOND OUTPUT TERMINALS, MEANS CONNECTING THE OUTPUT OF SAID STRETCHER AND FIRST OF SAID OUTPUT TERMINALS, MEANS CONNECTING SAID FIRST OUTPUT TERMINAL TO THE OUTPUT OF SAID SAMPLING GATE, A VOLTAGE COMPARATOR HAVING ONE OUTPUT AND TWO INPUT TERMINALS, SAID VOLTAGE COMPARATOR PRODUCING AN OUTPUT SIGNAL WHEN THE VOLTAGES APPLIED TO THE INPUT TERMINALS THEREOF BEAR A PREDETERMINED RELATIONSHIP TO EACH OTHER, MEANS TO APPLY A FAST SUBSTANTIALLY LINEAR RAMP VOLTAGE TO ONE INPUT TERMINAL OF SAID VOLTAGE COMPARATOR, MEANS CONNECTING THE OTHER INPUT TERMINAL OF SAID VOLTAGE COMPARATOR AND SECOND OF SAID OUTPUT TERMINALS MEANS RESPONSIVE TO SAID OUTPUT SIGNAL TO ACTUATE BOTH OF SAID GATES, A DIFFERENTIATOR RESPONSIVE TO THE RATE OF CHANGE OF VOLTAGE APPEARING ON THE FIRST OF SAID OUTPUT TERMINALS, A RAMP VOLTAGE GENERATOR HAVING INPUT AND OUTPUT TERMINALS, MEANS INCLUDING SAID DIFFERENTIATOR TO VARY THE SLOPE OF SAID RAMP VOLTAGE CONNECTING THE SAID FIRST OUTPUT TERMINAL AND THE INPUT OF SAID GENERATOR, AND MEANS CONNECTING THE OUTPUT OF SAID GENERATOR AND THE SECOND OF SAID OUTPUT TERMINALS.