Патент USA US2124805код для вставки
My 26, 1938. E. A. LAPORT 2,124,805 MIXING AMPLIFIER Filed June 19, 1956 Q\ v \\ \\.Q\ J ,4_ . .. Q913 = = , : ‘ 29 .5 2m%m. \. . "ma/é 53\m Han , mzn<m umno INVENTOR. é’éwlm/ld £1. gape u‘? ' BY 8‘ I i. ATTORNEY. Patented July 26, 1938 2,124,805 UNITED STATES PATENT OFFICE 2,124,805 7 MIXING AMPLIFIER Edmund A. Laport, Glen Ridge, N. J., assignor to Wired Radio, Inc., New York, N. Y., a corpora tion of Delaware Application June 19, 1936, Serial No. 86,129 2 Claims. (01. 179—171) This invention pertains in general to radio transmitted as carrier eliminated modulation circuits and specifically relates to a circuit for side band energy in discrete frequency ranges. combining signalling energy of different fre After passing through a ?lter and amplifying cir quencies. cuits, this energy is directed to the input circuit The principal object of the invention consists of electron tube 4 having the control electrode in providing an electron tube circuit for com thereof adjustably connected with the poten bining different signalling energy frequencies tiometer 3, as shown. The tube 4 is of the triode supplied from different sources without inter type, although other forms of tubes may be em action between the sources for producing an'out ployed, when desired. The anode circuit of the put current which is the algebraic addition of tube 4 includes a connection through a radio fre the plural input currents. quency choke 5 and thence to the positive “B” A further object comprises providing a sys tem for combining. modulated high frequency energy from which the carrier frequency has ' been eliminated, with a replacement carrier fre quency to reproduce desired signals. A further object consists in producing a mixing ampli?er circuit for amplifying and combining one frequency with another in an electron tube to produce a combined ampli?ed output. These and other objects will be apparent from the following, reference being had to the accom panying drawing which is a diagrammatic illus tration of a preferred embodiment of the inven 25 tion. ‘ The invention contemplates the provision of a system such as a wired radio receiving organiza tion which receives modulated high frequency energy comprising modulation side band energy 30 with the carrier frequency substantially elimi nated. A separate and distinct carrier frequency is supplied at the point of reception to be com bined with the modulation side band energy for replacement purposes to reproduce the original 35 signal. In accordance with the invention, the modulation side band energy and the indepen dent replacement carrier frequency are combined in a mixing ampli?er circuit to produce an alge braic addition of the two frequencies in a linear 40 ampli?cation process without inter-action be tween the two sources of frequencies. A multi electrode electron tube is provided with the elec trodes thereof respectively connected in a circuit arrangement for producing the desired mixing 45 and amplifying effect. Referring to the drawing in detail, a source of modulated high frequency energy is connected to the primary winding of a transformer 2 having a secondary winding connection to a poten 50 tiometer 3. The source I represents means for supplying modulation side band energy com prising one side band with the carrier frequency and other side band substantially eliminated, and may correspond to a power transmission network 55 over which several programs are simultaneously supply at terminal 6. ’ The carrier frequency source 8 is ‘connected with the primary of the transformer 9. The M source 8 comprises the means for supplying the 15 independent replacement carrier frequency cor responding to the frequency eliminated from the energy available at the source I. In accordance with the invention, means are provided for ad justing the phase relationship between the volt ages of the source I and source 8. ‘This carrier frequency may be impressed upon the transmis sion medium common to the source I or may be generated locally. The energy from the source 8 is directed through transformer 9 to a poten 25 tiometer I0 having an adjustable connection to the control electrode I I of a multi-electrode elec tron tube I2. The tube I-2 also includes a cath ode, a screen electrode I3, a suppressor electrode I4, and an anode I5. The anode I5 is connected 30 through the primary winding of a transformer I6 in an output circuit ‘connection including the positive “B” supply terminal 6. The transformer I6 includes a secondary output connection with a load circuit I‘I representing the utilization means, such as a program reproducing system. In accordance with the invention, the suppres sor electrode I4 is connected with the cathode of the tube I2 and is maintained at the same po tential as the cathode. The screen electrode I 3 is connected in the anode circuit of the tube 4, as shown. Other circuit components not described are of an obvious nature and known to those skilled in the art. In the operation of the system, the tubes 4 and I2 are provided with biasing potentials for optimum linear operating conditions as ampli ?ers. The potentiometers 3 and Ill are adjusted to provide an adjustable ratio or voltages from the sources I and 8. The modulation side band energy from the source I is then amplified by the tube 4 and directed to the screen electrode of the tube I2. Concomitantly, the carrier fre quency from the source 8 is directed to the con trol electrode II of the tube I2. The two fre 55 2,124,805 2 quencies are then combined in a linear ampli ?cation to produce algebraic addition frequen cies transmitted to the load circuit l'l. It is a feature of the invention that the circuit includ ing the screen electrode I3 is substantially the correct impedance to serve as a load for the cas cade stage of ampli?cation represented by the tube 4. However, when necessary and desired, a transformer may be interposed in this circuit to produce matched impedances, In operating the system, it may be desired to change the relation of the side band energy with respect to the replacement carrier frequen cy. To accomplish this, it is only necessary to 15 adjust the potentiometers 3 and I0 to bring about a desired relation of energy levels. In ‘accord ance with the invention, the two inputs are com pletely isolated from each other and no reaction between the inputs is possible through the mix ing system. Although a preferred form of the mixing ampli?er has been disclosed, it will be recognized that various changes and modi?ca tions as well as equivalent forms can be pro 2.? duced without departing from the intended scope of the invention. Accordingly, no limitation of the invention is intended other than as 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: 1. A mixing ampli?er comprising, a source of modulation side band energy with carrier fre quency substantially eliminated, a source of car rier frequency energy corresponding in frequen cy to said eliminated carrier, a load circuit, a 35 common combining circuit interconnecting said sources and said load circuit and including a multi-grid electron tube, the parameters of which are so chosen and adjusted with respect to the control grids thereof that said tube functions as a linear ampli?er only, said circuit being inter posed between one of said sources and said load and including a connection from one of the grids thereof with said one source, and means ‘con necting the other of said sources with another of the grids of said tube for supplying energy thereto under control of the source connected with said second mentioned grid whereby the foregoing arrangement as a whole operates for producing currents in said load circuit corre sponding respectively to said carrier frequency and said modulation side band to provide said modulation side band energy with a replaced car rier frequency. 2. A-mixing ampli?er comprising, a source of modulation side band energy with carrier fre quency substantially eliminated, a source of car rier frequency, energy corresponding in frequency to said eliminated carrier, a load circuit, a com mon combining circuit interconnecting said “' sources and said load,v circuit and including a multi-grid electron tube, the parameters of which are so chosen and adjusted with respect to the control grids thereof that said tube functions as a linear ampli?er only, said combining circuit ‘ including a connection from one of the grids thereof with one of said sources, and another electron tube connected with the other of said sources, said second electron tube being coupled with another of the grids of said ?rst mentioned ' tube for supplying ampli?ed energy thereto un der control of the source connected with said sec ond tube whereby the foregoing arrangement as a Whole operates for producing ampli?ed cur rents in said load circuit corresponding respec- - tively to said carrier frequency and said modula tion side band to provide said modulation side band energy with a replaced carrier frequency. EDMUND A. LAPORT.