Speed monitoring apparatus with a reference channel and a variable channel each employing a saturable core digital-to-analog converter

Claim 1

IN A SYSTEM FOR DETECTING THE DEFFERENCE BETWEEN THE SPEED OF A DEVICE AND A PREDETERMINED NORM, A REFERENCE CHANNEL, A SPEED CHANNEL, A REFERENCE OSCILLATOR, TRANSDUCER MEANS THAT PROVIDES OUTPUT PULSES AT A REPETITION RATE WHICH IS A FUNCTION OF THE SPEED OF SAID DEVICE, SAID REFERENCE CHANNEL INCLUDING FIRST PULSE FORMING MEANS COUPLED TO SAID OSCILLATOR FOR PROVIDING OUTPUT PULSES HAVING A REPETITION RATE RELATED TO THE FREQUENCY OF SAID OSCILLATOR, AND FIRS CONVERTER MEANS COUPLED TO THE OUTPUT OF THE PULSE FORMING MEANS FOR CONVERTING THE OUTPUT OF THE LATTER TO A FIRST ANALOG SIGNAL WHICH IS PROPORTIONAL TO THE FREQUENCY OF SAID OSCILLATOR, SAID SPEED CHANNEL INCLUDING SECOND PULSE FORMING MEANS COUPLED TO SAID TRANSDUCER MEANS FOR PROVIDING OUTPUT PULSES HAVING A REPETITION RATE THAT IS PROPORTIONAL TO THEPULSE RATE OF THE TRANSDUCER OUTPUT, AND SECOND CONVERTER MEANS COUPLED TO THE OUTPUT OF THE SECOND PULSE FORMING MEANS FOR CONVERTING THE OUTPUT OF THE LATTER TO A SECOND ANALOG SIGNAL WHICH IS PROPORTIONAL TO THE SPEED OF SAID DEVICE, MEANS RESPONSIVE TO SAID FIRST AND SECOND ANALOG SIGNALS FOR PRODUCING AN ERROR SIGNAL WHICH IS PROPORTIONAL TO THE DEVIATION OF SAID SPEED FROM A PREDETERMINED NORM, EACH OF SAID CONVERTING MEANS INCLUDING A SATURATING TRANSFORMER WITH A CORE AND A WINDING ON THE CORE COUPLED TO THE ASSOCIATED PRECEDING PULSE FORMING MEANS, THE RESPONSE CHARACTERISTIC OF EACH OF SAID TRANSFORMERS BEING AFFECTED BY TEMPERATURE CHANGES OF ITS CORE, THE CORE OF SAID TRANSFORMER IN THE SPEED CHANNEL BEING SUBJECTED TO TEMPERATURE FLUCTUATION IN RESPONSE TO VARIATION OF THE SPEED OF SAID DEVICE, SAID CORES BEING MAGNETICALLY ISOLATED FROM EACH OTHER, A COMMON VOLTAGE SUPPLY SOURCE CONNECTED TO SAID FIRST AND SECOND PULSE FORMING MEANS, AND HIGH RELUCTANCE HIGH THERMAL CONDUCTIVITY MEANS DEFINING A THERMAL CONDUCTION PATH CONNECTING SAID CORES TOGETHER TO MAINTAIN SAID CORES AT SUBSTANTIALLY THE SAME TEMPERATURE.