US1849632A - Volume control combining system - Google Patents

Description

March 15, 1932.

J. B. MOORE VOLUME CONTROL COMBINING SYSTEM Filed Nov. 16, 1928 INVENTOR 'rIN B. BL

MOORE ORNEY Patented Mar. 15,` 1932 UNITED STATES PATENT OFFICE JOHN B. MOORE, 0F RIVER-HEAD, NEW YORK, ASSIGNOR TO RADIO CORPORATION 0F AMERICA, A CORPORATION OF DELAWARE VOLUME` CONTROL COMBINING SYSTEM Application filed November 16, 1928. Serial No. 319,767.

This invention relates to diversity reception, and more particularly to volume contro'l therefor.

v having dierent fading characteristics, the

energies from which are finally combined together. The volume of the received energy 1s apt to vary between the extremes of almost complete fading at all of the antennas to no fading at any of the antennas. To overcome this it has been proposed to equip the receivers for the antennas each with a volume control, but this, in additionto the requirement of a considerable number of volumecontrols, suffers from two great disadvantages. One applies to code or speech-simulating signals, and is that the amplifiers of those antennas at which fading is prevalent are given increased gain, in consequence of which the noise level of the combined energy is greatly increased. The other applies more particularlyto speech-simulating signals, and is that the amplifier of an antenna at which the car-l rier is fading, while the sidebands Iare not, is given increased gain, vin consequence of which the distortion resulting from the beat between the sidebands is greatly increased.

To overcome the foregoing difculties is the primary object of my invention, which I attain by simultaneously controllingthe gain in the amplifiers of the separately collected energies all in response to the volume of the combined energy. In this manner the amplifiers experience equal changes in gain, so that the energy from an antennaat which no fading is present retains itsv magnitude relative to the small energy at antennas lo- L e cated at fading points, and dominates such energy, thereby improving the quality of the combined energy.

When dealing `with energies ,of sufficiently high frequency so that the phases of the received energies at the different antennas fiuctuate relative to one another, even though Y of like constant frequency, it is not feasible to combine the received energies directly together, and in such case my inventionv includes separately detecting the amplified "i energies, combining the detected energies so that the combination is substantially independent of the relative radio frequency phase atV the different antennas, and coni trolling the gain in the stepl of amplification of all of the collected energies in response to the volume of the combined detected energy,

f as Well as utilizing the combined energy to obtainthe desired signal.

My invention is more completely described in the following specification, which is accompanied by a drawing the single figure of which is a wiring diagram for a preferred form of my invention.

Referring to that figure there are a plurality of diversity antennas 2, 4 and 6, which are either geographically spaced, or located in different planes of polarization, or in `any other manner given dierent fading characteristics. These antennas are coupled by transmission lines 8, 10 and 12 to a plurality of radio frequency amplifiers 14, 16 and 18. The output from each of these amplifiersY is coupled to means to heterodyne the radio frequency energy to energy of intermediate frequency, indicated by the rectangles 20, 22 and 24. These means may comprise a source of locally generated energy of relatively high frequency and a separate heterodyne detector, or a single autodyne circuit in which the electron emission tube which functions as an oscillatoralso acts as a detector for combining the received and locally generated energies. The resulting energy of intermediate frequency is amplified in intermediate frequency amplifiers 26, 28 and 30; The amplified output is fed to detector tubes 32, 34 and 36, across the output circuit of each of which there is connected one or more low pass filter sections 38, 40 and 42, for by-passing the radio frequency components of the rectified energies. Y

rlhe signal components of the rectified energies are fed through leads 44, 46 and 48 `to a common lead 50, in series with which a source o lirect sniple, by conn ec'tiiig tte coupling impedance The circu :ind volume control impedance in series, and rouii-l tlie Jiine c iistunt cond inser and volume conl e tiel impedance in parallel, but i believe the firreingencnt illustrated ii tlie drawing is the moet lesireble one.

l clfiiin: si l. 'E lie inetliod of eiversity r ception Wliicli 1 f includes siinultii'ieouslv meshing a plurelit f collections of relatively `linrncreristics, seperately 5l i: ciesii su rily Aceleeee energies, separately Y i i e die ainplifed energies producing control ini iedsnce :i la: d IES connected to unidiieetionel unduletory energy, b 1S mieli are ceiifombining` the unidirectional energies, conn l trolling` the `frein in tlie aforesaid step of a1ntu s pliczition n. plurality of the collected enli li ergies in resp-e ise to the volume o1n the coino' biiied unidirectional energy, and translating to Clie combined energy.

2. Tl e method of diversity reception ivliicli includes collecting` the redieted energy at e plurality oi spaced points, seperately enr provided iii pz pi yin' Jlie collected energies, seperately circuiteros ce i the eiiplilied energies to obtain inipedcnce 68 the in C; undulatory iiiiidir xctionzzl energy, combining tube 'TO coupled tlie detected un' 1'rectionnl energies, controlelectrode of' tlic i if li Afrein in the aforesaid step of ampliroin npo'eiitizi the liciition of a plurality of tlie collected enercoupling impei conn zgies in response to the volume of the comdenser 24. Elie l'iined energy, end utilizinigT the combined uni- 70 may lie fu tional energy.

einplilier The inetliod et diversity reception Wliicli collectingl the radiated energy et zi lity of spaced poi its, separately empli- -ying and lieterodyniiig tlie collectede ergies to obtain :iinpliin ed energies of intermediate frequency, separately detecting the amplified eneigg'es to obtain unidirectional unfi `fitorj; energy, combining` the detected l. rectionzil iinduletory energies, controling tlie @ein in the aforesaid step of :impliienticn or" ezicii of the collected energies in :espoiise to the volume of the combined eni, .d utilizingv the combined energy for picture tra i stati n, or oLier It sliould lve i;

rality ol aiitcnnf teristies, pliii coupled thereto, trol responsive to energy from tlie rece Y controlling the finin.

ergies substeniillw." indepei d 4,-. 'llie combi nation with a diversity receivrndio frequency pliese at the ing system comprising e. plurality of enten ma i e provided inem nes of different fedine` characteristics and a the amplified ener io eonilniie plurzi 'cy or amplifying' receivers coupled the amplified ener., es c ieu lwtu thereto, common volume control respontiie volume of tlie combined unidinil undulitory energy from the receiv- Aor siniultinieously controlling the ainpl1- for volume control end exact number of giving); tliein istics, are not ine -f on gein in ell of the receivers, in order heterod *ne tli re i te redii e tlie noise level when the sioinel fades l a 1 n s n ineens te sinnliiij tue res n et :i receiving" point :ind/or the distortion refrequency energy V1s eiitiielu,y eg sultinfr from tlie beet between sidebands Wlienused,tlie voli, eccntrel ii'isjv i vili-cn cfirrier fades :it a receiving point to eitliei tlie riiiiiio frequency intermediate iii:Y i Well to both particule-l oiin for translating the combined uniiinc'liiletory energies.

rsity receiving system comprisplurality et antennas of different fadind of tie cori erecteristics, :i plurality of amplifiers tion circuit, me .ed thereto, ineens to seperately detect the amplified energies thereby obtaining uni* directional undulatory energies, means to combine the detected unidirectional undulatory energies, a common volume control responsive to the. combined undulatory energy for simultaneously controlling the gain in a plurality of the aforesaid amplifiers, and means to utilize the combined undulatory energy for translation.

6. A diversity receiving system comprising a plurality ofV spaced antennas, a plurality of amplifiers coupled thereto, means to separately detect the amplified energies to obtainV unidirectional undulatory energies, means to combine the detected unidirectional energies, a common volume control responsive to the combined energy for simultaneously controlling the gain in a plurality of the aforesaid amplifiers, and means to translate the combined unidirectional energy.

7. A diversity receiving system comprising a plurality of spaced antennas, a plurality of amplifiers and means to heterodyne the received energy to obtain amplified intermediate frequency energies coupled thereto, means to separately detect the amplified energies to obtain unidirectional undulatory energies, means to combine the Vdetected energies, a common volume control responsivevto the combined energy for simultaneously controlling the gain in each of theaforesaid amplifiers, and means to translate the combined unidirectional energy.

8. A diversity receiving system comprising a plurality of spaced antennas, a plurality of amplifiers coupled thereto, 'a plurality of d'etector tubes for detecting the amplified energies, a source of anode potential coupled to all of said detector tubes, a volume control impedance connected in series with said source of anode potential, a condenser cooperating with the impedance to establish the time constant of the volume control action, a connection from the volume control impedance to the control electrodes of the tubes of each of the aforesaid amplifiers for so varying the amplification gain therein as Will tend to keep the combined energy constant, a coupling impedance arranged in circuit with the volume control impedance to obtain a portion of the combined energy for utilization, an amplifier coupled to the coupling impedance, and a utilization circuit coupled to the amplifier.

9. A diversity receiving system comprising a plurality of spaced antennas, a plurality of amplifiers coupled thereto, means to separately heterodyne the received energies to obtain energies of intermediate frequency, means to separately amplify the intermediate frequency energies, a plurality of detector tubes for detecting the amplified energies, a source of anode potential coupled to all of said detector tubes, a volume control impedance connected in series With said source of anode potential, a condenser cooperating with ther impedance to establish the time constant of the volume control action, a connection from iso

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