Analog multiplier and square root extractor having a plurality of strain gages connected in a bridge circuit

Claim 2

Apparatus for deriving an analog signal directly proportional to the product of a force and a predetermined variable, said apparatus comprising: a base; a cantilever beam having one end fixed to said base; an actuator to supply the force to the other end of said beam; a bridge including first and second legs having first and second strain gages, respectively, fixed to opposite sides of said beam in positions to be placed in tension and compression, respectively, when said actuator deflects said other beam end in one direction, said bridge having third and fourth legs including third and fourth resistors, said bridge having first, second, third and fOurth corner junctions, said first strain gage being connected between said first and second junctions, said second strain gage being connected between said first and fourth junctions, said third resistor being connected between said second and third junctions, said fourth resistor being connected between said third and fourth junctions; first means connected between a point of reference potential and one of said second and fourth junctions to supply a potential thereto different from that of said point; second means connected between said point and the other of said second and fourth junctions to maintain the current from said other junction directly proportional to the magnitude of the predetermined variable; and third means connected from said first and third junctions for producing an output signal of a magnitude directly proportional to the difference between the potentials of said first and third junctions.

Claim 3

Apparatus for deriving an analog signal directly proportional to the product of a force and a predetermined variable, said apparatus comprising: a base; a cantilever beam having one end fixed to said base; an actuator to supply the force to the other end of said beam; a bridge including first and second legs having first and second strain gages, respectively, fixed to opposite sides of said beam in positions to be placed in tension and compression, respectively, when said actuator deflects said other beam end in one direction, said bridge having third and fourth legs including third and fourth resistors, said bridge having first, second, third and fourth corner junctions, said first strain gage being connected between said first and second junctions, said second strain gage being connected between said first and fourth junctions, said third resistor being connected between said second and third junctions, said fourth resistor being connected between said third and fourth junctions; first means connected between a point of reference potential and one of said second and fourth junctions to supply a potential thereto different from that of said point; second means connected between said point and the other of said second and fourth junctions to maintain the current from said other junction directly proportional to the magnitude of the predetermined variable; and third means connected from said first and third junctions for producing an output signal of a magnitude directly proportional to the difference between the potentials of said first and third junctions, said third means including first and second differential amplifiers each having plus and minus inputs, a fifth resistor connected from said first junction to the plus input of said first amplifier, a sixth resistor connected from said third junction to the plus input of said second amplifier, a capacitor connected between said plus inputs, fifth and sixth junctions connected to the minus inputs of said first and second amplifier, respectively, a seventh resistor connected between the output of said second amplifier and said sixth junction, a P-channel type field effect transistor having a source, a drain and a gate, an eighth resistor connected from the output of said first amplifier to said gate, a ninth resistor connected from the output of said second amplifier to said drain, a tenth resistor connected from said drain to said fifth junction, first and second potentiometers having first and second windings and first and second wipers, respectively, said first winding being connected between said fifth and sixth junctions, an eleventh resistor having one end connected from said sixth junction, said second winding being connected from the other end of said eleventh resistor to said fifth junction, fourth means to produce an input signal directly proportional to the predetermined variable, said second means being connected from said fourth means, fifth means connected from said fourth means to said second wiper to keep the current therefrom directly proportional to the magnitude of said input signal, and sixth means connected From said first wiper to said point of reference potential to maintain the current from said first wiper constant, the potential of said one junction being positive with respect to that of said point of reference potential.

Claim 4

Apparatus for deriving an analog signal directly proportional to the product of a force and a predetermined variable, said apparatus comprising: a base; a cantilever beam having one end fixed to said base; an actuator to supply the force to the other end of said beam; a bridge including first and second legs having first and second strain gages, respectively, fixed to opposite sides of said beam in positions to be placed in tension and compression, respectively, when said actuator deflects said other beam end in one direction, said bridge having third and fourth legs including third and fourth resistors, said bridge having first, second, third and fourth corner junctions, said first strain gage being connected between said first and second junctions, said second strain gage being connected between said first and fourth junctions, said third resistor being connected between said second and third junctions, said fourth resistor being connected between said third and fourth junctions; first means connected between a point of reference potential and one of said second and fourth junctions to supply a potential thereto different from that of said point; second means connected between said point and the other of said second and fourth junctions to maintain the current from said other junction directly proportional to the magnitude of the predetermined variable; and third means connected from said first and third junctions for producing an output signal of a magnitude directly proportional to the difference between the potentials of said first and third junctions, said third means including first and second differential amplifiers each having plus and minus inputs, a fifth resistor connected from said first junction to the plus input of said first amplifier, a sixth resistor connected from said third junction to the plus input of said second amplifier, a capacitor connected between said plus inputs, fifth and sixth junctions connected to the minus inputs of said first and second amplifier, respectively, a seventh resistor connected between the output of said second amplifier and said sixth junction, a P-channel type field effect transistor having a source, a drain and a gate, an eighth resistor connected from the output of said first amplifier to said gate, a ninth resistor connected from the output of said second amplifier to said drain, a tenth resistor connected from said drain to said fifth junction, first and second potentiometers having first and second windings and first and second wipers, respectively, said first winding being connected between said fifth and sixth junctions, an eleventh resistor having one end connected from said sixth junction, said second winding being connected from the other end of said eleventh resistor to said fifth junction, fourth means to produce an input signal directly proportional to the predetermined variable, said second means being connected from said fourth means, fifth means connected from said fourth means to said second wiper to keep the current therefrom directly proportional to the magnitude of said input signal, and sixth means connected From said first wiper to said point of reference potential to maintain the current from said first wiper constant, the potential of said one junction being positive with respect to that of said point of reference potential.

Claim 5

The invention as defined in claim 2, wherein said first means is also connected from said fourth means, said first means supplying a potential to said one junction equal to the sum of first and second potentials, said first potential being directly proportional to said input signal, said second potential being constant.

Claim 6

The invention as defined in claim 3, wherein said first potential is of a magnitude to maintain one of said first and third junctions at a constant potential relative to that of said point and independent of the magnitude of said input signal.

Claim 7

Apparatus for deriving an analog signal directly proportional to the product of a force and a predetermined variable, said apparatus comprising: a base; a cantilever beam having one end fixed to said base; an actuator to supply the force to the other end of said beam; a bridge including first and second legs having first and second strain gages, respectively, fixed to opposite sides of said beam in positions to be placed in tension and compression, respectively, when said actuator deflects said other beam end in one direction, said bridge having third and fourth legs including third and fourth resistors, said bridge having first, second, third and fourth corner junctions, said first strain gage being connected between said first and second junctions, said second strain gage being connected between said first and fourth junctions, said third resistor being connected between said second and third junctions, said fourth resistor being connected between said third and fourth junctions; first means connected between a point of reference potential and one of said second and fourth junctions to supply a potential thereto different from that of said point; second means connected between said point and the other of said second and fourth junctions to maintain the current from said other junction directly proportional to the magnitude of the predetermined variable; and third means connected from said first and third junctions for producing an output signal of a magnitude directly proportional to the difference between the potentials of said first and third junctions; fourth means being provided to produce an input signal directly proportional to said predetermined variable, said first and second means both being connected from said fourth means, said first means supplying a potential to said one junction equal to the sum of first and second potentials, said first potential being directly proportional to said input signal, said second potential being constant.

Claim 8

Apparatus for deriving an analog signal directly proportional to the product of a force and a predetermined variable, said apparatus comprising: a base; a cantilever beam having one end fixed to said base; an actuator to supply the force to the other end of said beam; a bridge including first and second legs having first and second strain gages, respectively, fixed to opposite sides of said beam in positions to be placed in tension and compression, respectively, when said actuator deflects said other beam end in one direction, said bridge having third and fourth legs including third and fourth resistors, said bridge having first, second, third and fourth corner junctions, said first strain gage being connected between said first and second junctions, said second strain gage being connected between said first and fourth junctions, said third resistor being connected between said second and third junctions, said fourth resistor being connected between said third and fourth junctions; first means connected between a point of reference potential and one of said second and fourth junctions to supply a potential thereto different from that of said point; second means connected between said point and the other of said second and fourth junctions to maintain the current from said other junction directly proportional to the magnitude of the predetermined variable; and third means connected from said first and third junctions for producing an output signal of a magnitude directly proportional to the difference between the potentials of said first and third junctions; fourth means being provided to produce an input signal directly proportional to said predetermined variable, said first and second means both being connected from said fourth means, said first means supplying a potential to said one junction equal to the sum of first and second potentials, said first potential being directly proportional to said input signal, said second potential being constant.

Claim 9

The invention as defined in claim 3, wherein said first potential is of a magnitude to maintain one of said first and third junctions at a constant potential relative to that of said point and independent of the magnitude of said input signal.

Claim 10

A square root extractor comprising: first means to provide an input signal; first, second and third integrators; at least a first inverter connected from the output of said first means; a first sampling switch connected from the output of said first inverter to the input of said first integrator; a second sampling switch connected from the output of said first means to the input of said second integrator; a third resetting switch connected to said first integrator; a fourth resetting switch connected to said second integrator; a fifth switch connected from the output of said first integrator to the input of said third integrator; a sixth switch connected from the output of said second integrator to the input of said third integrator; second means connected from the output of said third integrator for producing a bilevel output signal, said bilevel signal being produced synchronously with the output signal of said third integrator, said bilevel signal changing levels at the maximum and mInimum values of said third integrator output signal; and third means connected from the output of said second means for alternately opening and closing all of said switches in accordance with the level of said bilevel signal, said second, third and sixth switches being closed while said first, fourth and fifth switches are opened, and vice versa, said third means being adapted to close said first, fourth and fifth switches beginning at the peaks of the output signal of said third integrator, the rate at which pulses are generated by said second means being directly proportional to the square root of the magnitude of said input signal.

Claim 11

A square root extractor comprising: first means to provide an input signal; first, second and third integrators; at least a first inverter connected from the output of said first means; a first sampling switch connected from the output of said first inverter to the input of said first integrator; a second sampling switch connected from the output of said first means to the input of said second integrator; a third resetting switch connected to said first integrator; a fourth resetting switch connected to said second integrator; a fifth switch connected from the output of said first integrator to the input of said third integrator; a sixth switch connected from the output of said second integrator to the input of said third integrator; second means connected from the output of said third integrator for producing a bilevel output signal, said bilevel signal being produced synchronously with the output signal of said third integrator, said bilevel signal changing levels at the maximum and mInimum values of said third integrator output signal; and third means connected from the output of said second means for alternately opening and closing all of said switches in accordance with the level of said bilevel signal, said second, third and sixth switches being closed while said first, fourth and fifth switches are opened, and vice versa, said third means being adapted to close said first, fourth and fifth switches beginning at the peaks of the output signal of said third integrator, the rate at which pulses are generated by said second means being directly proportional to the square root of the magnitude of said input signal.

Claim 12

The invention as defined in claim 7, wherein a pulse counter is connected from the output of said second means to register the integral of said square root with respect to time, said square root integral being directly proportional to total mass flow of a fluid in a pipeline when the magnitude of said input signal is directly proportional to the product of the differential pressure across an orifice therein and the density of the fluid therein.

Claim 13

The invention as defined in claim 8, wherein said second means includes a second inverter, first and second threshold detectors, a flip-flop, and first and second AND gates, said first detector producing a high output at the maximum amplitude of the output signal of said third integrator, said second detector producing a low output at the minimum amplitude of the output signal of said third integrator, said first gate having one input from the ''''0'''' output of said flip-flop and another input from the output of said first detector, both of said detectors having their inputs connected from the output of said third integrator, said first gate having an output connected to the set ''''1'''' input of said flip-flop, said second inverter being connected from the output of said second detector to one input of said second gate, said second gate having another input connected from the ''''1'''' output of said flip-flop, said second gate having an output connected to the set ''''0'''' input of said flip-flop, said third means being connected from the ''''1'''' output of said flip-flop.

Claim 14

The invention as defined in claim 7, wherein said second means includes a second inverter, first and second threshold detectors, a flip-flop, and first and second AND gates, said first detector producing a high output at the maximum amplitude of the output signal of said third integrator, said second detector producing a low output at the minimum amplitude of the output signal of said third integrator, said first gate having one input from the ''''0'''' output of said flip-flop and another input from the output of said first detector, both of said detectors having their inputs connected from the output of said third integrator, said first gate having an output connected to the set ''''1'''' input of said flip-flop, said second inverter being connected from the output of said second detector to one input of said second gate, said second gate having another input connected from the ''''1'''' output of said flip-flop, said second gate having an output connected to the set ''''0'''' input of said flip-flop, said third means being connected from the ''''1'''' output of said flip-flop.

Claim 15

Apparatus for deriving an analog signal directly proportional to the product of a force and a predetermined variable, said apparatus comprising: a base; a cantilever beam having one end fixed to said base; an actuator to supply the force to the other end of said beam; a bridge including first and second legs having first and second strain gages, respectively, fixed to opposite sides of said beam in positions to be placed in tension and compression, respectively, when said actuator deflects said other beam end in one direction, said bridge having third and fourth legs including third and fourth resistors, said bridge having first, second, third and fourth corNer junctions, said first strain gage being connected between said first and second junctions, said second strain gage being connected between said first and fourth junctions, said third resistor being connected between said second and third junctions, said fourth resistor being connected between said third and fourth junctions; first means connected between a point of reference potential and one of said second and fourth junctions to supply a potential thereto different from that of said point; second means having an output lead, said second means maintaining the potential of said output lead directly proportional to the predetermined variable; a pick-off junction; a fifth resistor connected between said output lead and said pick-off junction; variable resistance means connected between the other of said second and fourth junctions and said pick-off junction; a voltage amplifier connected from said pick-off junction and a fixed potential to said variable resistance means to vary the resistance of said variable resistance means between said other and pick-off junctions in a manner to keep the potential of said pick-off junction effectively constant; and third means connected from said first and third junctions for producing an output signal of a magnitude directly proportional to the difference between the potentials of said first and third junctions.

Claim 16

Apparatus for deriving an analog signal directly proportional to the product of a force and a predetermined variable, said apparatus comprising: a base; a cantilever beam having one end fixed to said base; an actuator to supply the force to the other end of said beam; a bridge including first and second legs having first and second strain gages, respectively, fixed to opposite sides of said beam in positions to be placed in tension and compression, respectively, when said actuator deflects said other beam end in one direction, said bridge having third and fourth legs including third and fourth resistors, said bridge having first, second, third and fourth corNer junctions, said first strain gage being connected between said first and second junctions, said second strain gage being connected between said first and fourth junctions, said third resistor being connected between said second and third junctions, said fourth resistor being connected between said third and fourth junctions; first means connected between a point of reference potential and one of said second and fourth junctions to supply a potential thereto different from that of said point; second means having an output lead, said second means maintaining the potential of said output lead directly proportional to the predetermined variable; a pick-off junction; a fifth resistor connected between said output lead and said pick-off junction; variable resistance means connected between the other of said second and fourth junctions and said pick-off junction; a voltage amplifier connected from said pick-off junction and a fixed potential to said variable resistance means to vary the resistance of said variable resistance means between said other and pick-off junctions in a manner to keep the potential of said pick-off junction effectively constant; and third means connected from said first and third junctions for producing an output signal of a magnitude directly proportional to the difference between the potentials of said first and third junctions.