US1719189A - Electrical signal amplifying and repeating system - Google Patents

Electrical signal amplifying and repeating system Download PDF

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Publication number
US1719189A
US1719189A US50555A US5055525A US1719189A US 1719189 A US1719189 A US 1719189A US 50555 A US50555 A US 50555A US 5055525 A US5055525 A US 5055525A US 1719189 A US1719189 A US 1719189A
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tubes
tube
current
currents
filament
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US50555A
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English (en)
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Benjamin F Miessner
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Priority to US50555A priority Critical patent/US1719189A/en
Priority to GB20286/26A priority patent/GB256994A/en
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B15/00—Suppression or limitation of noise or interference
    • H04B15/005—Reducing noise, e.g. humm, from the supply

Definitions

  • the amplifying and repeating devices to render them operative particularly where other than steady sources of potential are 7 used for energizing the filament and plate circuits of three-electrode vacuum tubes.
  • This invention constitutes an improvement over that described in my co-pending application Serial No. 29,859 of May 13, 1925, in which I system for amplifying and repeatingelectrical signals wherein a plurality of threeelectrode vacuum tubes were energized from a source of alternating current, together with means and procedure for eliminating the bum that usually results from. the use of such currents. I have found that substantialimprovement is obtained by certain further procedure with properly chosen and co-ordinatcd apparatus, which further improvements are the subject of my present invention.
  • VT indicates two tubes arranged for AA radio frequency amplification
  • VT indicates a detector tube.
  • VT and VT indicate two tubes arranged for a'udiofrequency amplification.
  • the plate circuits of these tubes are energized by unsteady direct current derived from rectifying and filtering preferably cycle alternating current, the arrangement comprising anordinary lamp plug LP connecting the primary of a power transformer PT through a switch S and an 55 indicating lamp and safetl fuse L to the source of supply.
  • An ordinary three-elece reception of radio signals wherein three-- rectifying tube.
  • a tor action is a little with means for eliminating hum trode vacuum tube VT is converted in effect into a two-electrode tube for rectification purposes by connecting the grid and plate elements together as shpwn.
  • a secondary winding S energizes the filament of the secondary winding S provides the currents to be rectified vacuum tube VT and filtered by the combination comprising the two parallel con-- densers C and C and the series resistance by the R, preferably made variable for proper control of the energy supply to the plate circuits of the operating vacuum tubes.
  • the resistances R and R divide the rectified and filtered energy into two potentials, one usually l'llglLfOI the amplifiertubesof the system, and supplied thereto by the line B, and one usually low for the detector tube of the system, and supplied thereto by the line' B".
  • the line PR "provides a plate return for connection to the several filaments.
  • the secondary winding S and lines AA supply unrectified alternating current for heating the filaments of the first four vacuum tubes of the system.
  • the extension secondary windings S S and the lines A i A supply unrectified alternating current VT loud speaker LS, and is a more powerful tube than the preceding ones. Good deteccur'rent adjustment than amplifier tube action, so that the filament circuit of detector tube VT- includes a current control resistance R. i a
  • the grids of all of the vacuum tubes are connected to a GR, which line includes a grid biasing battery CB and which is connected to the filaments through-a variable contact X associated with a connected across the filament supply lines fier VT 'through the action of variable condenser VC and variable inductance or variometer VL.
  • the amplified high frequency currents are selectively transferred from tube VT to tube VT through radio frequency transformer with the assistance of variable condenser V0
  • the high fremore critical to filament common grid return vor line resistance or potentiometer includes a variable inductance or variometer VL to permit of adjusting the coupling for best results with variation of frequency of received radio signals.
  • the detected currents are assed to vacuum tube VT through an io frequency transformer AF,
  • levers i, 2, 3 and t cooperate to open the filament circuit and the rid circuit of vacuum tube Vl It is very important to open up the grid circuit of vacuum tubefVT and tie-energize the tube when the telephones are connected to the first stage of audio frequency amplification because, if left connected and energized, stray fields from the alternating current system in the receiver will be picked up by the circuits ofthis last and free tube and amplified to create considerable annoyance from the loud speaker.
  • the impure currents resulting from rectification and filtration supplie to the plate circuits (2 ⁇ , the nlternating current supply for heating the filaments periodically varies the potential across the terminals of the filainents alternately positive and negative, and, since the grids must be connected tosome point of the filament, there results a varying potential upon the grids; and (3), the temperatures of the filaments vary somewhat in consonance with the alternating currents heating the filament, resulting in a varving creating annoying The audio electron emission by the'filaments at double the frequency of the alternating currents.
  • the disturbing currents resulting from the conditions I have outlined above are of an extremely low frequency compared to the radio frequency signal currents handledby the radio frequency portion of my receiver, and are also low in frequency compared to the great majority of signal currents handled in the audio frequency portion of my receiver. Very little or no difficulty therefore arises in vacuum tubes VT and VT and their associated circuits because the radio frequency transformers which convey the currents through and beyond these tubes pass to a negligible degree the disturbing currents. The trouble hegins in the detector tube VT where the audio frequency transformer AF more or less efficiently passes forward disturbances arising in this tube.
  • the high voltage across the filaments of existing tubes is most undesirable for alternating current a heating, because the wide variation in potential across the filament increases the tendency to impress a varying potential on the grid through its necessary connection to the filament, It is customary, in trying to mini mize theefl'ect on the grid, to connect the grid return. to a theoretical mid-point of a potentiometer connected across the filament supply line, or to a theoretical mid-point or center tap of the filament transformer secondary winding. At best, the mid-point connection is only theoretical, and it is readily apparent that the greater the total difference of potential across the filament, the greater Wlll be the disturbance arising from an imperfect mid-point connection.
  • the first our vacuum tubes have the low voltage and high inertia temperature fila-- to towards complete hum elimination
  • my presentinvention refers particularly to a system embodying this added feature.
  • ⁇ Vhile I have utilized a radio receiver for the purpose of illustrating and describing trodes, means for impressing the alternating currents to beamplified upon said system,
  • a system including three-electrode amplifiers of alternating mm-rents having grid, filament and plate electrodes, means for impressing the alternating currents to be amplified upon said system, means for passing the amplified currents from one tube to .another including connections between thegridsand filaments of said tubes, means for operatively energizing said tubes including atransformer ments, the filaments of said tubes being supplying alternating current, to said filaadapted to consume energy for heating at a rate determined by a predominant current Icomponenh-means for uniformly distributmg the potentialand phase variations in said filament energizing system due to said alternating currents, and means connecting said grids to such "a point of saiddistributed potential'and phase as to cause variations of potential to be impressed on said grids in such a manner as to neutralize variations in the amplified plate'current in thelast of said tubes caused by'the unsteady filament heating currents.
  • Means for supplying alternating current at different voltages to the filaments of different three-electrode vacuum tubes of an amplifying system and for providing a connection between the grid circuits of the tubes and the filament supply system said means consistin of a transformer having a pria secondary winding, a pair of filamentsupply taps connected to intermediate points of. the secondary winding at opposite sidesof the neutral point of the secondary winding, an impedance connected across the taps and a grid-connection tap connected to an intermediate point of said impedance.
  • Means for supplying alternating current at dificrent voltages to the filaments of different three-electrode vacuum tubes of an amplifying system and for providing a connection between the grid circuits of tubes and the filament supply system said means consisting of a transformer having a pri mary and a secondary winding, a pair of filament supply taps connected to intermediate points of the secondary winding at oppo site sides of the neutral point of the secondary winding, a resistance connected across said taps and a grid-connection tap adjustable to different points of said resistance.
  • a system including three-electrode vacuum tube amplifiers of alternating currents, having grid, filament and plate electrodes, means for impressing the alternating currents to be amplified upon said system, means for passing the amplified currents from one tube to another including connections between the grids and filaments of said tubes, means for operatively energizing said tubes including means for heating the filaments of said tubes from an unsteady source of potential, the filaments of said tubes being adapted to consume energy for heating at a low operating temperature at a rate determined by a predominant current component, means for uniformly distributing the potential-and phase variations in said filament heating system due to.
  • a plurality of three-electrode vacuum tubes arranged for multi-stage amplification of signaling current, the filaments of one or more of the tubes in advance ofthe last tube being massive and heated by current of relatively low voltage and the filament of the last tube bein ada ted for heating by current of relatively hig voltage, means for energizing said'filaments from a com-i rnon source of alternating current energy whereby periodic disturbing variations are created in the plate circuits of said tubes, and means for passing to the grid circuit of the last tube some of the disturbing energy of a preceding tube of phase after amplification to oppose the disturbing energy-in the plate circuit of the lastltube.
  • a signal current amplifying system including a pair of three-electrode vacuum tubes connected in cascade relation, one of said tubes having a cathode producing relatively small and the other of said tubes having a cathode producing relatively large disturbingvariations when energized with periodically fluctuating current, means for energizing the cathodes of both of said tubes, from a common source of periodically fluctuating current, said tubes being so associated in said system that the disturbing energy of the first of'said tubes is introduced into. the grid circuit of the second of said tubes in a phase to oppose the disturbing energy in the plate circuit of the second said tube.
  • a cascade system for amplifying signal current of high frequency modulated at audible frequency including a three-electrode vacuum functioning as a detector followed by one or more three-electrode vacuum, tubes functioning as audio amplifiers, means for energizing the oathodes-of all of said tubes from a common source of audible frequency periodically fluctuating current, the cathode of said de-,
  • athree- 1n following audio amplifier” tube producing tube having a cathode which when energized current, and means for passing to the grid circuit of'said'power tube someof the disturbing energy of saidpreceding tube or tubes of phase after amplification to opin the plate circuit of said outputtube.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Rectifiers (AREA)
  • Amplifiers (AREA)
US50555A 1925-08-17 1925-08-17 Electrical signal amplifying and repeating system Expired - Lifetime US1719189A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US50555A US1719189A (en) 1925-08-17 1925-08-17 Electrical signal amplifying and repeating system
GB20286/26A GB256994A (https=) 1925-08-17 1926-08-17

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US50555A US1719189A (en) 1925-08-17 1925-08-17 Electrical signal amplifying and repeating system

Publications (1)

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US1719189A true US1719189A (en) 1929-07-02

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GB (1) GB256994A (https=)

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Publication number Publication date
GB256994A (https=) 1928-02-17

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