Optical telemetry devices

Claim 1

IN OPTICAL TELEMETRY APPARATUS FOR MEASURING THE DISTANCE BETWEEN AN OBSTACLE AND A PREDETERMINED POINT AND OF THE TYPE HAVING A LIGHT SOURCE DISPOSED AT SAID PREDETERMINED POINT FOR ILLUMINATING THE OBSTACLE, AN OPTICAL SIGHTING SYSTEM DISPOSED IN THE VICINITY OF SAID SOURCE FOR RECEIVING LIGHT RAYS REFLECTED BY SAID OBSTACLE AND TWO PHOTO-ELECTRIC CELLS DISPOSED ADJACENT ONE ANOTHER IN THE FOCAL PLANE OF SAID OPTICAL SYSTEM AT A FIXED INTERVAL AND DISPLACEABLE IN SAID FOCAL PLANE ALONG A STRAIGHT LINE AT RIGHT ANGLES TO THE LIGHTING LINE JOINING SAID SOURCE AND SAID OBSTACLE FOR DETERMINING THE POSITION IN WHICH SAID CELLS ARE EQUALLY LIGHTED, WHEREBY THE DISTANCE BETWEEN THE CENTER OF SAID INTERVAL IN SAID POSITION OF THE CELLS AND SAID LIGHTING LINE IS RELATED TO THE DISTANCE TO BE MEASURED; THE IMPROVEMENT COMPRISING A ROTATABLE DEVICE DISPOSED IN THE PATH OF THE LIGHT BEAM EMITTED BY THE SOURCE AND HAVING TWO SETS OF APERTURES FOR SAID BEAM, WHICH SETS OF APERTURES HAVE DIFFERENT WIDTHS AND SPACINGS FOR GENERATING TWO LIGHT RAYS RESPECTIVELY MODULATED AT DIFFERENT FREQUENCIES, MEANS FOR DRIVING SAID DEVICE IN ROTATION, TWO FREQUENCY CHANNELS RESPECTIVELY CONNECTED TO THE TWO PHOTO-ELECTRIC CELLS AND RESPECTIVELY CORRESPONDING TO THE FREQUENCIES OFF THE TWO MODULATED LIGHT RAYS RECEIVED BY SAID CELLS AFTER REFLECTION BY THE OBSTACLE, ADDING MEANS CONNECTED TO SAID TWO FREQUENCY CHANNELS, A SINGLE AUTOMATIC GAIN AMPLIFIER FED BY SAID ADDING MEANS, AND MEANS SUPPLIED BY SAID AMPLIFIER FOR GENERATING AN ERROR SIGNAL RELATED TO THE DIFFERENCE EXISTING BETWEEN THE AMPLITUDES OF THE SIGNALS TRANSMITTED THROUGH SAID FREQUENCY CHANNELS, COMPRISING MEANS CONNECTED TO THE SINGLE AUTOMATIC GAIN AMPLIFIER FOR DIVIDING THE COMPLEX SIGNAL DELIVERED BY SAID AMPLIFIER INTO TWO SERIES OF AMPLIFIED SIGNALS RESPECTIVELY MODULATED AT THE FREQUENCIES OF THE TWO MODULATED LIGHT RAYS, MEANS FOR RESPECTIVELY DETECTING SAID AMPLIFIED SIGNALS AND A DIFFERENTIAL COMPARATOR CONNECTED TO SAID DETECTING MEANS FOR DELIVERING THE ERROR SIGNALS, WHEREBY SAID TWO PHOTOELECTRIC CELLS CAN BE DISPLACED TO A POSITION IN WHICH THE AMPLITUDE OF THE SIGNALS ARE EQUAL AND SAID ERROR SIGNAL BECOMES NULL, AND IN WHICH POSITION SAID CELLS ARE EQUALLY LIGHTED AND CAN THEN SERVE AS A REFERENCE FOR EVALUATING THE DISTANCE BETWEEN THE OBSTACLE AND SAID PREDETERMINED POINT.