US2718591A - Function generator - Google Patents

Function generator Download PDF

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Publication number
US2718591A
US2718591A US247046A US24704651A US2718591A US 2718591 A US2718591 A US 2718591A US 247046 A US247046 A US 247046A US 24704651 A US24704651 A US 24704651A US 2718591 A US2718591 A US 2718591A
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Prior art keywords
voltage
tube
cathode
electrically connecting
means electrically
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US247046A
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Jr Walter R Hedeman
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Bendix Aviation Corp
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Bendix Aviation Corp
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Priority to US247046A priority Critical patent/US2718591A/en
Priority to FR1067956D priority patent/FR1067956A/en
Priority to GB21991/52A priority patent/GB720126A/en
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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/28Details of pulse systems
    • G01S7/285Receivers
    • G01S7/295Means for transforming co-ordinates or for evaluating data, e.g. using computers
    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06GANALOGUE COMPUTERS
    • G06G7/00Devices in which the computing operation is performed by varying electric or magnetic quantities
    • G06G7/12Arrangements for performing computing operations, e.g. operational amplifiers
    • G06G7/16Arrangements for performing computing operations, e.g. operational amplifiers for multiplication or division
    • G06G7/163Arrangements for performing computing operations, e.g. operational amplifiers for multiplication or division using a variable impedance controlled by one of the input signals, variable amplification or transfer function

Definitions

  • This invention relates generally to electric function generation and more particularly to circuits for generating inverse functions related to a mechanical motion.
  • the primary object of the present invention is to provide a simple and economical inverse function generator.
  • Another object is to provide an improved function generator which is stable in operation and capable of supplying useful load current.
  • a further object resides in provision for adjusting the shape and relative position of the inverse function generated to satisfy varying requirements.
  • Fig. l is a schematic diagram of a circuit of the present invention employed in an antenna system
  • Fig. 2 shows a modification
  • Fig. 3 is a schematic diagram of a circuit of the invention having sensitivity and level adjustments.
  • a variable width waveguide antenna 11 having a movable element 12 driven in oscillatory linear motion by a driving means 13.
  • a current supply tube 14 supplies current to the series adjustable resistors R1, R2 and R3 from a D. C. source 15.
  • the high potential end of R1 is connected to control a suitably referenced amplifier tube 16 which in turn controls the current tube 14.
  • the value of R1 is varied in accordance with the position of the element 12 by a suitable linkage thereto.
  • the output voltage e appearing across R1, R2 and R3 is applied to a utilization means such as a deflection circuit 17 of a cathode-ray tube 18.
  • the linear movement of the element 12 causes a scanning motion of the beam of the antenna 11 which is related to the displacement of element 12 by a hyperbolic or inverse function.
  • the linear motion (translational or angular) which varies the resistance of R1 linearly, produces an output voltage 20 which can be made the analogue of the scanning antenna beam position as follows.
  • the gain provided by control tube 16 is made sufiiciently high to maintain the voltage 21 essentially constant regardless of the setting of R1 Within the nited States Patent O Patented Sept. 20, 1955 ice operating range of the system. For this condition the output voltage is which varies inversely with the value of R1.
  • the phase of the change in R1 with respect to the antenna beam motion i. e. whether R1 increases or decreases With respect to beam motion from an arbitrarily chosen zero position determines the sign of the functional relationship between the dependent and independent variables.
  • the voltage eh may be utilized as the output voltage. This arrangement will, in general, be limited to small load currents to prevent any appreciable voltage drop in R3 therefrom.
  • a modification of the voltage divider R1, R2, R3 is shown in which R1 is constant and at is established across R3 and a fractional part of R1, namely, XR1 where X has values between zero and unity.
  • the resultant expressions for so and en are again hyperbolic and of the form and
  • Fig. 3 a modification is shown in which R3 is made up of two series resistances Rz-l-R4.
  • Rz-l-R4 for this arrangement the expression (1) becomes which may be a more convenient form for adjusting the parameters to obtain a fit with a given curve.
  • the two resistors of value R2 in Fig. 3 are ganged to maintain their equality for all settings.
  • a source of adjustable reference potential E such as an independent regulated D. C. supply 21 to provide a sensitivity adjustment controlling the available output voltage swing of as.
  • the D. C. level of 20 is adjusted to any desired value by returning the voltage divider via lead 22 to a potential Ec from another suitable independent D. C. voltage source such as regulated supply 23.
  • the operation of the circuit of Fig. 3 in a particular case would be as follows.
  • a cathode-ray tube deflection circuit drive it is desired to drive the deflection stage from near cutoff to near gridcurrent voltage levels.
  • the proper shape curve to fit the analogue is obtained by the choice of values of R1, R2, R4, using curve fitting techniques such as obtaining a fit at two or more points by substituting values for the variables at three points and solving for the unknown values.
  • the amplitude of voltage change is adjusted by adjusting the voltage E, since this is a sensitivity control.
  • the level at which the swing starts is then set by adjusting EC, which is a bias or level control.
  • the output of the device is then the desired form of signal for the particular case under consideration.
  • a system for producing a voltage which is an inverse function of a linear mechanical motion input comprising: a constant voltage direct current source; positive and negative terminals associated with the said source;
  • a triode vacuum tube means electrically connecting the plate of the said tube to the said positive terminal; three resistors; an element associated with one of the said resistors to vary the value of the resistance thereof; said resistors being serially and electrically connected such that the said variable resistor is located in the center position thereof; means electrically connecting the said serially connected resistors between the cathode of the said tube and the said negative terminal; an amplifying tube; a fourth resistor; means electrically connecting the said fourth resistor between the plate of the said amplifying tube and the said positive terminal; a biasing means; said biasing means electrically connected between the cathode of the said amplifying tube and the said negative terminal; means electrically connecting the said plate of the said amplifying tube to the grid of the said triode tube; means electrically connecting the grid of the said amplifying tube to the terminal of said variable resistor that is electrically closer to the said cathode of the said triode tube; and means imparting a mechanical motion to said element to vary the value of the said variable resist
  • a system for producing a voltage which is an inverse function of a linear mechanical motion input comprising: a constant voltage direct current source; positive and negative terminals associated with said source; a vacuum tube having a plate, a cathode and at least one grid; means electrically connecting the plate of said tube to the said positive terminal; a resistance voltage divider having an intermediate point movable over a range of values for changing the ratio of the resistances of said divider on opposite sides of said point; means electrically connecting the said voltage divider between the cathode of said tube and the said negative terminal; an amplifying tube having a plate, a cathode and at least one grid; a resistor; means electrically connecting the said resistor between the plate of the said amplifying tube and the said positive terminal; a biasing means; said biasing means electrically connected between the cathode of said amplifying tube and the said negative terminal; means electrically connecting the said plate of said amplifying tube to the grid of said vacuum tube; means electrically connecting the grid of Said ampl

Description

FUNCTION GENERATOR Walter R. Hedeman, Jr., Baltimore, Md., assignor to Bendix Aviation Corporation, Towson, Md., a corporation of Delaware Application September 18, 1951, Serial No. 247,046
2 Claims. (Cl. 250-27) This invention relates generally to electric function generation and more particularly to circuits for generating inverse functions related to a mechanical motion.
Many function generators are known in the art for producing desired mathematical relationships between physical quantities. The establishment of a desired inverse functional relationship between two quantities has in the past been accomplished with relatively complex arrangements.
The primary object of the present invention is to provide a simple and economical inverse function generator.
Another object is to provide an improved function generator which is stable in operation and capable of supplying useful load current.
A further object resides in provision for adjusting the shape and relative position of the inverse function generated to satisfy varying requirements. I
These and other objects of the invention are achieved by providing a controlled output voltage across an output impedance element which is under control of the voltage across a portion of the impedance. Circuit arrangements are provided whereby the control voltage across the portion of the impedance is maintained substantially constant regardless of the ratio that portion bears to the whole output impedance so long as the control range is not exceeded. Under these conditions'motion imparted to a variable element to vary the ratio the portion bears to the whole generates as the controlled output voltage an inverse analogue of the motion.
In the drawings:
Fig. l is a schematic diagram of a circuit of the present invention employed in an antenna system;
Fig. 2 shows a modification; and
Fig. 3 is a schematic diagram of a circuit of the invention having sensitivity and level adjustments.
Referring to Fig. 1 there is shown a variable width waveguide antenna 11 having a movable element 12 driven in oscillatory linear motion by a driving means 13. A current supply tube 14 supplies current to the series adjustable resistors R1, R2 and R3 from a D. C. source 15. The high potential end of R1 is connected to control a suitably referenced amplifier tube 16 which in turn controls the current tube 14. The value of R1 is varied in accordance with the position of the element 12 by a suitable linkage thereto. The output voltage e appearing across R1, R2 and R3 is applied to a utilization means such as a deflection circuit 17 of a cathode-ray tube 18.
In operation the linear movement of the element 12 causes a scanning motion of the beam of the antenna 11 which is related to the displacement of element 12 by a hyperbolic or inverse function. The linear motion (translational or angular) which varies the resistance of R1 linearly, produces an output voltage 20 which can be made the analogue of the scanning antenna beam position as follows. The gain provided by control tube 16 is made sufiiciently high to maintain the voltage 21 essentially constant regardless of the setting of R1 Within the nited States Patent O Patented Sept. 20, 1955 ice operating range of the system. For this condition the output voltage is which varies inversely with the value of R1. This is a general form of an expression for a hyperbolic function which can be made to fit a given hyperbola by adjustment of the parameters R2 and R3 and the addition of a D. C. voltage for level adjustment, if required. The phase of the change in R1 with respect to the antenna beam motion (i. e. whether R1 increases or decreases With respect to beam motion from an arbitrarily chosen zero position) determines the sign of the functional relationship between the dependent and independent variables.
In applications where the hyperbolic term is desired free of the constant term (:21), the voltage eh may be utilized as the output voltage. This arrangement will, in general, be limited to small load currents to prevent any appreciable voltage drop in R3 therefrom.
Referring to Fig. 2 a modification of the voltage divider R1, R2, R3 is shown in which R1 is constant and at is established across R3 and a fractional part of R1, namely, XR1 where X has values between zero and unity. The resultant expressions for so and en are again hyperbolic and of the form and In Fig. 3 a modification is shown in which R3 is made up of two series resistances Rz-l-R4. For this arrangement the expression (1) becomes which may be a more convenient form for adjusting the parameters to obtain a fit with a given curve. The two resistors of value R2 in Fig. 3 are ganged to maintain their equality for all settings. The cathode of tube 16 in Fig. 3 is returned to a source of adjustable reference potential E such as an independent regulated D. C. supply 21 to provide a sensitivity adjustment controlling the available output voltage swing of as. The D. C. level of 20 is adjusted to any desired value by returning the voltage divider via lead 22 to a potential Ec from another suitable independent D. C. voltage source such as regulated supply 23.
The operation of the circuit of Fig. 3 in a particular case would be as follows. In an application, such as a cathode-ray tube deflection circuit drive, it is desired to drive the deflection stage from near cutoff to near gridcurrent voltage levels. This implies a specific voltage range of swing between specific voltage levels. The proper shape curve to fit the analogue is obtained by the choice of values of R1, R2, R4, using curve fitting techniques such as obtaining a fit at two or more points by substituting values for the variables at three points and solving for the unknown values. The amplitude of voltage change is adjusted by adjusting the voltage E, since this is a sensitivity control. The level at which the swing starts is then set by adjusting EC, which is a bias or level control. The output of the device is then the desired form of signal for the particular case under consideration.
Obviously, other degenerative amplifier systems may be used to drive the output impedance combination. Such amplifiers need only to maintain substantially constant the voltage across the portion of the output impedance which supplies the input thereof for the purpose of this invention.
What is claimed is:
1. A system for producing a voltage which is an inverse function of a linear mechanical motion input, comprising: a constant voltage direct current source; positive and negative terminals associated with the said source;
a triode vacuum tube; means electrically connecting the plate of the said tube to the said positive terminal; three resistors; an element associated with one of the said resistors to vary the value of the resistance thereof; said resistors being serially and electrically connected such that the said variable resistor is located in the center position thereof; means electrically connecting the said serially connected resistors between the cathode of the said tube and the said negative terminal; an amplifying tube; a fourth resistor; means electrically connecting the said fourth resistor between the plate of the said amplifying tube and the said positive terminal; a biasing means; said biasing means electrically connected between the cathode of the said amplifying tube and the said negative terminal; means electrically connecting the said plate of the said amplifying tube to the grid of the said triode tube; means electrically connecting the grid of the said amplifying tube to the terminal of said variable resistor that is electrically closer to the said cathode of the said triode tube; and means imparting a mechanical motion to said element to vary the value of the said variable resistor thereby producing a voltage variation across the said serially connected resistors which is an inverse function of the said mechanical motion.
2. A system for producing a voltage which is an inverse function of a linear mechanical motion input, comprising: a constant voltage direct current source; positive and negative terminals associated with said source; a vacuum tube having a plate, a cathode and at least one grid; means electrically connecting the plate of said tube to the said positive terminal; a resistance voltage divider having an intermediate point movable over a range of values for changing the ratio of the resistances of said divider on opposite sides of said point; means electrically connecting the said voltage divider between the cathode of said tube and the said negative terminal; an amplifying tube having a plate, a cathode and at least one grid; a resistor; means electrically connecting the said resistor between the plate of the said amplifying tube and the said positive terminal; a biasing means; said biasing means electrically connected between the cathode of said amplifying tube and the said negative terminal; means electrically connecting the said plate of said amplifying tube to the grid of said vacuum tube; means electrically connecting the grid of Said amplifying tube to said movable point; and means imparting a mechanical motion to the said movable point to produce a voltage variation across said voltage divider which is an inverse function of said mechanical motion.
References Cited in the file of this patent UNITED STATES PATENTS 2,268,790 White Ian. 6, 1942 2,398,916 Brewer Apr. 23, 1946 2,407,458 Spielman Sept. 10, 1946 2,409,456 Tolson Oct. 15, 1946 2,461,514 Bowers Feb. 15, 1949 2,483,644 Kelsey Oct. 4, 1949 2,510,687 DeVore June 6, 1950 2,525,698 Mackenzie Oct. 10, 1950 2,527,753 McConnell Oct. 31, 1950 2,567,880 Frommer Sept. 11, 1951
US247046A 1951-09-18 1951-09-18 Function generator Expired - Lifetime US2718591A (en)

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US247046A US2718591A (en) 1951-09-18 1951-09-18 Function generator
FR1067956D FR1067956A (en) 1951-09-18 1952-08-25 Function generator
GB21991/52A GB720126A (en) 1951-09-18 1952-09-01 Function generator

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2829281A (en) * 1954-09-08 1958-04-01 Philips Corp Transistor switching circuit
US3309511A (en) * 1963-03-18 1967-03-14 Robert H Begeman Hyperbolic function generator

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NZ523946A (en) * 2003-01-31 2004-06-25 Carl Ernest Alexander Portable hygiene compositions comprising a semi-solid gel and active ingredients in bead form for use in personal oral, dental or skin care

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2268790A (en) * 1938-06-01 1942-01-06 Emi Ltd Voltage stabilizing device for electric supply systems
US2398916A (en) * 1945-03-22 1946-04-23 Sperry Gyroscope Co Inc Electronic voltage regulator
US2407458A (en) * 1943-12-06 1946-09-10 Philco Corp High-voltage regulator circuit
US2409456A (en) * 1944-01-29 1946-10-15 Rca Corp Radiant energy locating system
US2461514A (en) * 1946-05-02 1949-02-15 Jack L Bowers Voltage regulator
US2483644A (en) * 1947-01-21 1949-10-04 Gilfillan Bros Inc Electronic angle indication with particular reference to radar systems
US2510687A (en) * 1944-11-17 1950-06-06 Rca Corp Brightness control for pulse echo position indicator systems
US2525698A (en) * 1945-05-11 1950-10-10 Hazeltine Research Inc Compensated voltage regulator
US2527753A (en) * 1945-07-09 1950-10-31 Robert A Mcconnell Radio object locating system
US2567880A (en) * 1947-07-05 1951-09-11 Clippard Instr Lab Inc Voltage regulator

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2268790A (en) * 1938-06-01 1942-01-06 Emi Ltd Voltage stabilizing device for electric supply systems
US2407458A (en) * 1943-12-06 1946-09-10 Philco Corp High-voltage regulator circuit
US2409456A (en) * 1944-01-29 1946-10-15 Rca Corp Radiant energy locating system
US2510687A (en) * 1944-11-17 1950-06-06 Rca Corp Brightness control for pulse echo position indicator systems
US2398916A (en) * 1945-03-22 1946-04-23 Sperry Gyroscope Co Inc Electronic voltage regulator
US2525698A (en) * 1945-05-11 1950-10-10 Hazeltine Research Inc Compensated voltage regulator
US2527753A (en) * 1945-07-09 1950-10-31 Robert A Mcconnell Radio object locating system
US2461514A (en) * 1946-05-02 1949-02-15 Jack L Bowers Voltage regulator
US2483644A (en) * 1947-01-21 1949-10-04 Gilfillan Bros Inc Electronic angle indication with particular reference to radar systems
US2567880A (en) * 1947-07-05 1951-09-11 Clippard Instr Lab Inc Voltage regulator

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2829281A (en) * 1954-09-08 1958-04-01 Philips Corp Transistor switching circuit
US3309511A (en) * 1963-03-18 1967-03-14 Robert H Begeman Hyperbolic function generator

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GB720126A (en) 1954-12-15
FR1067956A (en) 1954-06-21

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