US1878252A

US1878252A - High frequency transmission system

Info

Publication number: US1878252A
Application number: US537935A
Authority: US
Inventors: Albert H Taylor
Original assignee: Wired Radio Inc
Current assignee: Wired Radio Inc
Priority date: 1931-05-16
Filing date: 1931-05-16
Publication date: 1932-09-20
Anticipated expiration: 1949-09-20

Description

Sept, 20, 1932. "A. H. TAYLOR HIGH FREQUENCY TRANSMISSION SYSTEM Filed May 16, 1951 M hr M w m W m Patented Sept. 20, 1932 ALB RT H, T YLORQoFL WASHINGTON, ign rs'rnrorr on, COLUMB1A, iissrenon To w ser-j i nnnr mo, or lnnw-Ya r,n. Y., seoiaron'nrlon or DELAWARE j 1 nren rnneuniicrrnensnrssroit sYs'rEivr Appl ication fil ed May' ifi, iseirs rialjno; 527,935; I '4 y invention'relates broadly tohi h quency transmission systems and more pa 'ticularly to an arrangement of high frequency" oscillator and power amplifier having means for preventing reactionary effects between the power amplifier and high frequency oscil-v l'ator circuits. v

One of theobjects of myinvention is to provide a circuit arrangement fora high tre- 19 quency signal transmission system employing tetrodes in the oscillator and power. amplifier r stages with coupling'means between the oscillatorand power amplifier arranged-to prevent reactionary effects from'thepower amplifier upon the oscillator; a

Another obj ect' of my invention is to provide a circuit arrangement for' couplingtetrodetubes in the masteroscillator and power amplifier stages of a signaltransmission system with means compensatingfor reactionary eifects arising in the power amplifier -with respect 'to-the master oscillator;

Still another object" of my. invention is vto provide acircuit arrangement for a signal transmission system employingmultiple electrode electron tubes in the master oscillator and power amplifier stageswith circuits coupling the output of the oscillator withthe input of the power amplifier including a connectionextending to one of the electrodes of the oscillator and operating to compensate for reactionary'effects occurring in the power amplifierstage for stabilizing the frequency of operation of the oscillator circuit.

A further object of my invention is to provide a circuit arrangement for coupling a master oscillator with the power'amplifier of asignal transmission system havin'gmeans for maintaining the frequency of operation of the oscillator system substantially constant without the employment of any "form of electromechanical vibrator. I i 7 Other and further objectsofmyinvention reside in a constant frequency signal. trans- IIllSSlOIl system whlch operates ndependently :of piezo electricor electromechanical control as set'forth more fully in the'specification oscillator tube l is completed fromjhecontrolgrid 10 through'condense'r 2 and induc-' tance; 3,:to the mid-tap 4: ther'eofand there Referring t o the drawing detailg the sys grid The'rinput ircuitiof ma as after through condenser 5 tothe mid tapfi of the cathode power supply transformer 7. I have diagrammatically illustrated the cathodecircuit'as supplied from the alternating current generator 8 which connects tofthe .a

[primary winding 9 of'the power transformer 7. The secondary winding 10 of the power transformer 7 is connected tOI the cathode circuit 11 of themaster oscillatortube 1 andthe power amplifier-ltube 12'. ,Thecathode gcireach side thereof, thementen point being grounded-through lead 15 as "shown!" The output circuit of thei -master oscillator 1 extends from the anodelb to one end of the in iductance 3 and to the midpoint 4 thereof and through le'adld-to the positive side of the 'sistance path 19 which connects to the mid-.

conductor 15v of the cathode heating circuit '85 a which "connects to the negative side of the high vpotential source 17 The auxiliary grid 1d ;recei.ves a predetermined potential through the'chokecoil 20 connected to the tap 21 on the potentiometer 22. t The potentiometer 22 is connected across the high potential source 17, Tap 21 is adjustable along the potentiometer 22 for selectively impressing the desired operating potential upon the auxiliary .grid 1d. A connection 23 extends from the auxiliarygrid through an adjustable .balanc'econdenser 24 to an adjustable -tap 25 onthe inductance 3, The tap 25 is shiftable along the inductance- 3 to a position which brings-aboutlthe compensating action which iwill be hereinafter describedpfor. ob- I taining the stabilized operation of the master oscillator. The master oscillator 1 is adj usted to the required frequency by means of the tuning condenser 26.

The power amplifier tube 12 includes a cathode 12a, an anode 126, a control grid 12c and an auxiliary grid 12d. The cathode 12a is heated from the filament heating circuit 11, the bypass condensers 27 being. connected across the cathode circuit and the midpoint connected to the mid-conductor 15 as shown. The control grid 120 is connected through condenser 28 with the adjustable tap 29 on the inductance 3, the tap being disposed between the midpoint l and theend of the inductance 3 which connects to the anode 1b. The desired negative potential is supplied to the control grid 120 from suitable source 30 through the choke coil 31 to the grid 120 as shown. The output circuit of the power amplifier includes a connection from the anode 12b to resonant circuit 32 which contains inductance 33 shunted by a variable capacity 34.,

The opposite end of the resonant circuit 32 is connected to lead 35 to the positive terminal 36 of the source of potential 17. The auxiliary grid 12d is supplied with positive potential from the source of potential 17 through a resistor or impedance 37. Radio frequency bypass condenser 38 connects between the cathode circuit and the auxiliary grid 12d. Radio frequency bypass condenser 39 connects across the source of high potential 17 in the position shown. 7

The tetrode 1 constituting the master oscillator is not used as a screen grid tube as is the case of the tetrode which constitutes the power amplifier 12. It will be observed that the auxiliary grid 1d of the master oscillator tube 1 does not have a connection to the cathode through a bypass condenser but is independently supplied with potential through the choke coil 20 from'the tap 21 on the 'potentioineter 22. The power amplifier tube 12 functions as a screen grid tube by virtue of the connection of the auxiliary grid 12d as shown.

When the load circuit of a power amplifier is tuned to resonance corresponding in frequency to that frequency determined by the adjustment of the elements 3 and 26 in the coupling circuit between the master oscillator and the power amplifier, there is a tendency for a small change of the frequency of the master oscillator circuit to take place when the power amplifier passes through the resonance point due to unbalanced load reactions.

In the system of my invention, this tendency is compensated by placing an opposing radio frequency voltage on the auxiliary grid 1d and this is accomplished by con necting the grid through the balancing condenser 24 to a source of potential at tap 25 on inductance 3. A variation of the potential on the auxiliary grid 161 also manifests itself in the master oscillator by changing the frequency of oscillation thereof, and this phenomenon is utilized to compensate for the change of frequency of the master oscillator due to disturbances in the coupling inductance by applying to the auxiliary grid 1d a potential proportional to that of the disturbancesand of such polarity as to neutralize or. compensate for the frequency the power amplifier system. By shifting the tap 25 along the inductance 3 and varying the effective capacity of the balancing condenser 24, a slight disturbance in inductance 3 brought about by tuning the resonant circuit 32through resonance is caused to slight- 1y change the potential of auxiliary grid 1d of the tetrode 1 which operates as the master oscillator to partially compensate for the resonance reaction. Where such surges are of relatively large amplitude, the compensating potential is increased by shifting the tap 25 alonginductance 3 to a position where a greater potential is introduced upon the auxiliary grid 1?) and where the surges due to changes in resonance conditions are of smaller amplitude, the position of the tap 25 is shifted along inductance 3 .to introduce a proportionate amount of compensating voltages in the auxiliary grid 10?.

While I have described my invention in one of its preferred embodiments, I desire that it be understood that modifications may be made and that no limitations upon my invention are intended other than are imposed by the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is as follows:

1. In a high frequency transmission system, a master oscillator circuit, a power amplifier circuit, said circuits each including a tetrode, input and output circuits interconnecting the electrodes of said tetrodes. a

resonant coupling circuit disposed between the circuits of sald master osclllator and the input circuit of said power amplifier, a resonant circuit connected with the output in said resonant coupling circuit for compensatmg for reactionary effects developed by changing the resonant condition in the resonant circuit in the output of said power amplifier. 7

ISO

nant circuit connected with the output of In a high frequency transmission system, a master oscillator circuit, a power ,am-

plifier circuit, said circuits each including a tetrode, input and output circuits interconnecting the electrodes of said tetrodes, a resonant coupling circuit disposed between the'circuits of said master oscillator and the input circuit of said power amplifier, a

resonant circuit connected with the output of said power amplifier and a tap on said resonant coupling circuit connected to one of the electrodes in the tetrode comprising said master" oscillator for establishinga current path to said masteroscillator for compensat plifier circuit, said circuits each including a tetrode, input and output circuits interconnecting the electrodes of said tetrodes, a resonant coupling circuit'disposed between the circu ts of said master oscillator and the input circuit of said power amplifier, a resosaidpower amplifier, and aradio frequency path extending from a tap on said resonant coupling circuit to one of the electrodes of the tetrode constituting said master oscillator for establishing a current path to said master 'oscillatorfor compensating for reactionary effects developed by. changing the resonant condition in the resonant circuit inthe out-; 7

' resonant circuitconnected with the output put ofsaid power amplifier.

4. In a high frequency transmission system, a master oscillator circuit,'a power am? plifier circuit, said circuits each including a tetrode, input and outputcircuits interconnectlng the electrodes of said tetrodes, a resonant coupling circuit disposed between the circuits of said master oscillator and thein putcircuit of said poweramplifier, a reso-,- nant circuit connected with the output of said power amplifier, and a selectively tuned path interconnecting said resonant coupling circuit and one of the electrodes ofthe tetrode constituting said master; oscillator for establishing a current path to said master os-' cillator for compensating for reactionary-effects developed by changing the resonant condition inthe resonant circuit in the output of said-power amplifier. i

5. In a high frequency transmissionsys tem, a master oscillator circuit, a power ainplifier circuit, said circuits each including an electron tube having a cathode,.. an anode, a control grid and an auxiliary grid, input and output circuits interconnecting said control grid, said'cathode and said anode, a resonant coupling circuit disposed between the output circuit of said master oscillator and the input circuit of said power amplifier, a reso.- nant circuit connected with the output of said ,the'outputof saidpower'amplifier-i p 6..In a high frequencytransmission 'syspoweramplifier, and-a connection extending vbetween ar selected point in-said iresonant coupling circuit to the auxiliary grid of said tem, a master oscillator-circuit, a poweram plifier1circuit-,said circuits each includingan electron tube having a'cathode, an anode, a control grid and an auxiliaryv grid, lnp'ut'and output circuits interconnecting said control grid; said cath'ode' and lsaid anode; 1a. resonant coupling circuit disposed. between the, 7 output circuit of said master oscillator and theinput circuit of said power amplifier, a resonant circuit connected with the output of said power amplifier, and a tuned radio frequency path betweena point in Sald resonant couplingcircuit'to said auxiliary grid for a compensating ,for reactionary efiects developed by changing-the resonant condition in the resonant circuit in the output of said power amplifier;

7. In a high frequency transmission sys-o tem,a master oscillator circuit, a power amplifier circuit, said circuitseach including s an electron tube having a cathode, an anode, V a control grld and an auxlliary grid, input and output circuits interconnecting said conof said power amplifier, atuned radio fr equency path'extendingbetween a point in said resonant coupling circuit tosaid auxiliary grid of said master oscillator tube for j ,trol grid, said cathode and said anode, a resoestablishing a current path to saidmaster osx,

cillator for compensating for reactionary effects developed by changing the resonant condition, in the resonant-circuitin the output of sald poweramplifier, a source'of potentialfor energizing the circuits of said electron tubes, a potentiometer connected "across-said sourceof potential, and a connection leading from anladjustable tap on said potentiometer to the auxiliary grid of a the tube constituting said master oscillator.

8. In a high frequency transmission systerm a master oscillator circuit, a power am plifiercircuit, said circuits each including an electron tube having a cathode, an anode, a I control grid and an auxiliary gr1d,1nput and output circuits interconnecting saidcontrol grid, said cathode and said anode, a resonant coupling circuit disposed between the output circuit of said master oscillator-and'the input circuit of said power amplifier, aresonant circuit connected with the output of said power amplifier, a tuned radio frequency path extending between ,apoint in said grid of said master oscillator tube for establishing a current path" to said master oscil lator for compensating'forreactionary effects developed by changing'tlie resonant condition in the resonant circuitin the output of said power amplifier, a" source of potential for energizing the circuits of said electron tubes, a potentiometer connected across said source of potential, a connection leading from'an adjustable tap on saidpotentiorneter to the auxiliary grid of the tube constituting said master oscillaton'and means in said last mentioned connection for excluding surges of radio frequency currents through said potentiometer.

ALBERT TAYLOR.