Method and device for measuring the amplitude ratio of two electric signals, more particularly for the measuring of the density of the atmosphere

Claim 1

APPARATUS COMPRISING FIRST AND SECOND POTENTIOMETERS OF IDENTICAL ELECTRICAL CHARACTERISTICS AND ADAPTED TO RECEIVE TWO ELECTRICAL SIGNALS THE RATIO OF WHICH IS TO BE MEASURED, INTERCONNECTED MOVABLE CONTACTS ADAPTED TO MAKE CORRESPONDING MOVEMENTS ON RESPECTIVE OF SAID POTENTIOMETERS, A REFERENCE VOLTAGE SOURCE, FIRST POTENTISON MEANS COUPLED TO THE CONTACT OF SAID FIRST POTENTIOMETER TO COMPARE THE VOLTAGE TAPPED THEREFROM WITH THE VOLTAGE OF SAID SOURCE, SERVO MEANS RESPONSIVE TO SAID COMPARISON MEANS TO ADJUST THE CONTACT OF SAID FIRST POTENTIOMETER ZEROIZE THE VOLTAGE TAPPED THEREFROM, A THIRD POTENTIOMETER COUPLED TO THE MOVABLE CONTACT OF SAID SECOND POTENTIOMETOR AND INCLUDING A MOVABLE CONTACT, SECOND COMPARISON MEANS COUPLED TO THE LATTER SAID CONTACT TO COMPARE THE VOLTAGE TAPPED THEREBY WITH THE VOLTAGE OF SAID SOURCE, AND SERVO MEANS RESPONSIVE TO SAID COMPARISON MEANS TO ADJUST THE CONTACT OF SAID THIRD POTENTIOMETER TO ZEROIZE THE VOLTAGE TAPPED THEREFROM, THE ADJUSTED POSITION OF THE LATTER SAID CONTACT INDICATING THE RATIO OF SAID TWO ELECTRICAL SIGNALS.