Патент USA US2403615код для вставки
July 9, 1946- ~ - R. c. SANDERS. JR 2,403,615 FREQUENCY RESPONSIVE CIRCUIT ' Filed Nov. 30, 1942 F/90M1H9U0D7/p. Bnventor ‘Dovo-en C?anDeQ/JQ: as @% (Ittorneg Patented July 9, 194a ' 2,403,615 . r umrso STATES rA'rsnrol-"Fics FREQUENCY RESPONSIVE CIRCUIT Royden C. Sanders, Jr., Hightstown,_N. J., assignor ' to Radio Corporation of America, a corporation of Delaware‘ ' Application November 30, 1942,- Serial No. 467,445 3 Claims._ -(Cl.- 175-4320) ' tion is connected to ground through to a capaci tor 2|. The grid 23 of an ampli?er tube 25 is con- ' nected to the diode plate 19 through a resistor 21. A load resistor 28 is'connected from the an ode IQ to the arm 3| of a tap switch 33. A plu rality of resistors 35 are connected in series with an adjustable resistor 31 across a direct current source-38. The taps 38 of the switch 33 are con be used to control motors or indicators in re sponse to changes in‘the frequency of an alternat ing current source of relatively low‘ power capa 2 is grounded, and the anode I! of the other sec This invention reiates to frequency responsive circuits, and more. particularly to a ‘system for operating a relatively rugged relay in response to signals of predetermined or selected frequencies. when the input is above a preselected frequency, the relay is operated to one position; when the input is below’ this frequency the relay is oper ated to another position. Thus the device may 10 nected between the resistors 35 so that an adjust able portion of the direct current voltage may be applied to the load resistor 29. A relay ll is con= nected in the anode circuit of the tube 25. One application of this system is in the control The device operates as iollows: of aircraft by means of a radio altimeter of the type described on pages 86-90 of Civil Aeronautics 15 Audio frequency voltage applied across the re bility. ' - - sistor I is ampli?ed in the tube l. The amplitude of the input voltage is made high enough to cut Bulletin No. 29, published by the Civil Aero nautics Administration. The radio altimeter pro vides an audio frequency output directly propor tional in frequency to the height of the airplane 03 the tube on the negative peaks and cause satu ration on the positive peaks. This clips the peaks of the ampli?ed voltage, producing an output of rectangular wave form. The time constant of above the ground. The airplane may be con trolled to ?y at some selected level by operating motors connected to the elevator surfacesin re sponse to variations in the output frequency of the altimeter from the frequency corresponding to the selected level. A frequency responsive re lay system for this purpose must withstand the vibration and acceleration forces occurring in ?ight without failure or false operation. Accordingly, it is one object of this invention to provide an improved method of and means for 30 the condenser 8 and the resistor ‘i is made so small that the condenser 9 will be almost 109% dis charged or charged in one half cycle of the high est frequency at which this device is to operate. The positive half cycle of the rectangular wave causes the condenser 9 to be charged through the diode section I3, H. The negative half cycle of the rectangular wave discharges the condenser Si mined value in the frequency of an alternating through the diode section i5, 59 into the con» denser 2| and hence stores its discharge current in the condenser 2|. The condenser 2i discharges through the load resistor 29, potentiometer 3i and voltage. the direct current source 38. The condenser e controlling a relativelyheavy and insensitive re lay in response to variations from a predeter _ - . Another object is to provide an improved de 35 charges and discharges through a voltage range Esw equal to the peak'to peak amplitude of the vice which is uniformly sensitive to frequency rectangular wave voltage across the resistor '5 variations, independent of the selected frequency. minus any average negative voltage Ef developed A further object is to provide an- improved across the ‘condenser 2|. Hence every cycle, method .of and means for controlling the damp (Esw-t-Ej) C. Coulombs or (Esw+E.f) (C) (F) ing of a relay or other electromagnetic device, to amperes will be passed by the diode section 15, i9, prevent erratic operation in response to sudden where F is the frequency of the applied signal. variations of the control voltage or received signal. and C is the capacitance of the capacitor H. H ' Eb is the positive bias potential developed between These and other objects will become apparent to those skilled in the art upon consideration of 45 point SI and ground, and R. is the resistance or the following description. with reference to the the resistor 29, then accompanying drawing, which is a schematic cir E‘!=Eb— (EswieEf) (C) (F) (R) cuit diagram of an embodiment of the invention. when E! is negative only. It is seen therefore A pentode ampli?er tube i is provided, with a grid leak 3, a self bias resistor I, and a load re sistor 1. The plate of the tube I is coupled through a capacitor 9 to a double diode II. The plate I! of one diode section and the cathode I! of the other diode section are connected to the capacitor I. The cathode II of the ?rst section 50 that the voltage E! is the resultant some at the positiveibias voltage Eb from point 3| to ground and the negative voltage developed across the re“ sister 2! due to the current (Esw-l-Ef) (C) (F). when E! is negative, the above relations hold ex actly. However if the current (Esw+El) (C) (F) 9,408,015 - ' 4 is not su?icient to make El negative, then enough ' steady D.-C. current will flow thru the diodes quency responsive circuit for operating a relay in to input of a predetermined fre quency. a unidirectional voltage, related in mag II, II and II, I! to maintain E! at approximately sero volts. Thus El‘ will not vary appreciably with frequency until the current ' nitude to the frequency of the input, is derived. , An adiustable unidirectional voltage is opposed ' . to the frequency derived voltage, and the result ing diiference voltage is used to control an am is large enough to cause E! to become negative. I pli?er tube connected to the relay. Above that point E1‘ will vary with frequency be 1 claim. as my invention: coming more nonlinear as E] becomes an appre 1. A frequency responsive relay system com ciable part of Esw. The rate of change of E! with respect to frequency is: prising a limiter, a recti?er coupled to the out put of said limiter through a capacitor, a second ' capacitor in series with said recti?er, a discharge path for said second capacitor including a direct in- 2811+ E1). we) df l-CJ'R ‘ i The condenser 21 discharges through the loa resistor II, potentiometer 3! and the direct cur rent source 8|. Thus the negative voltage E! increases with fre quency, becoming nonlinear with respect to fre quency when E! is an appreciable fraction of the square wave voltage Esw. The voltage at the Eb tap ll is adjusted to a value correspondingtothe frequency at which the relay is to beoperated. . when the frequency is below the selected value, ‘ the grid 23 of the tube II is positive and the relay is energized. maintaining the contacts 43 in their ll current source connected to oppose the voltage produced across said second capacitor by the current ?owing through said recti?er, a second recti?er connected across said second capackor and said ?rst recti?er and poled oppositely there to, an ampli?er tube with-its control grid coupled to said discharge circuit, a relay connected in ._ the anode circuit of said ampli?er tube, and means for adjusting the voltage of said direct current source which is-applied to said discharge circuit, whereby said voltage overcomes the volt; age produced across said second capacitor at a upper positions. When the voltage!!! becomes slightly greater in magnitude than the voltage at the tap II, the grid 23 becomes negative and the anode current of the tube 2| decreases, reducing the energization of the relay II and causing the movable contacts 4! to go to their lower positions. ' In order to vary the frequency at which the relay 4| is operated the tap 3|‘ may be moved to ,th ~~ then ope ' : contact II. The system is described above, cutting of! the tube 2! as the frequency increases about the selected value. Thus the same number of cycles predetermined frequency or input to said limiter. 2. The method of operating a relay in response to variations in the frequency of an alternating voltage comprising the steps of deriving a uni directional voltage related in magnitude to said frequency, opposing said voltage to a second uni directional voltage of adjustable magnitude, con- ' trolling a power circuit in accordance with the amount by which said second voltage exceeds said , ?rst voltage, and energizing said relay with said power. 3. The method of operating a relay in response to variations in the frequency of an alternating per second deviation will actuate thereigy at any 40 voltage comprising the steps of deriving a uni selected frequency.‘ The resistor 21 and the ca directional voltage related in magnitude to said. pacitor 2| are so proportioned as to have a time constant equal to’or greater than that of the _ I frequency, opposing said voltage to a second uni- ' directional voltage of adjustable magnitude, con capacitor 2i and resistor 2!. This causes the a direct current in accordance‘ with in anode current of the tube 25 to change at the l5 trolling, amount by which said second voltage exceeds said same rate.with a decrease in frequency as 'it does with an increase in frequency, preventing erraticopcrationoftherelayll. - The invention has been described‘ as a fre ?rst voltage, and energizing said relay with said current. - a ROYDEN C. SANDERS, Js.