US1654920A

US1654920A - Multichannel radio system

Info

Publication number: US1654920A
Application number: US584958A
Authority: US
Inventors: Chaffee Emory Leon
Original assignee: Individual
Current assignee: Individual
Priority date: 1922-08-29
Filing date: 1922-08-29
Publication date: 1928-01-03
Anticipated expiration: 1945-01-03

Description

Jan. 3, 1928. 1,654,920 E. L. CHAFFEE w 1 MULTICHANNEL RADIO SYSTEM Filed Auzlz. 1922 v 71v VENZOR HIS/I TTORNEY Patented Jan. 3, 1928.

UNITED STATES IIOBY LEON Panzer! OFFICE.

Cmm, O I' BELMONT, MASSACHUSETTS, ASSIGNORTOiJOHN' HAYS WORD, .13., 0F GLOUCESTER, IASSAGEUSETT$- xumrcnammr. aanio srs'rmr.

Application fled August 29, 1982. Serial No. 584,958.

This invention relates to systems for the transmission and reception of radlant energy and has for its object to provide im-- proved methods and means for the transmission of intelligence by Hertzian waves whereby a message may be reliably received with a minimum of interference or blocking; to provide means for receivin a message over a plurality of channels havlng different characteristics independently thus eflectually preventing blocking by malicious outelders; and to provide methods and means for producin from different sources of energy a plura 'ty of series of beats of the same frequenc for controlling an indicating device, where y any one of the series of beats may be employed for controlling the indicating device. Still other objects of the invention will appear from the following description taken in connection with the accompanyin drawing.

The sing e figure of the drawing shows diagrammatically one form of receiving system embodying the invention.

In the drawin there is shown so much of a so-called wireless receiving stem as is necessary to an'understanding o the invention. It is understood that the sending equipment (not shown) is adapted to impress upon the ether, a plurahty of continuous waves all modulated at difierent frequencies but in a similar manner.

- The illustrated system comprises a loop 10 and a second loop 11 arranged at right anglies thereto, both loops being positioned at an angle of substantially to the direction from which the radiant ener .is expected to be received. The 100 10 orms part of a closed circuit 12 inclu g an adustable condenser 13 and resonant to apredetermined frequency. This frequency w1ll be hereinafterrepresented by the symbol A 1.

The circuitof the loop 10 is operatively connected to a three-electrode electron device 14 comprising a sealed container having therein a usual heated filament for emitting electrons, a plate 18' upon which the electrons impinge, and a grid 19 for controlling their passage. The grid is connected to the loop 10 so as to be controlled by electrical oscillations caused to be set up therein by electro-magnetic or so-called Hertzian waves.

The loop 11 forms part of a similar closed circuit 15 which includes an adjustable condenser 16 and is adjusted to be resonant to a second frequency A 2 differing from the first-namedfrequenc A 1.- The circuit of the loop 11 is similar y connected to the grid of a second three electrode electron device 17 having a usual heated filament, grid and he secondary winding of each of the transformers 21 and 23 is included in an oscillatory circuit, such as 40 and 41 respectively, each including means for tuning the circuit, such as a variable condenser or the like, to be resonant to the respective modulating frequencies.

Each oscillatory circuit 40 and .41 includes a primary winding of a transformer, v

such as and 51 respectively, the secondary windings of which form parts of closed

oscillatory circuits

52 and 53 including adjustable condensers 54 and 55 respectively.

The circuit 52 is operativel connected to a three-electrode eiectron device 56 and is arranged to act upon its grid 19 to control the output circuitof the plate 18 thereof. Similarly, the close circuit 53 is operatively connected to the g 'd 19 of a corresponding thermionic device 7.

The plate circuits of the devices 56 and 57 include respectively windings 60 and 61 of a transformer 62. Inductively cou led to these windings is a tertiary win in which is included in a resonant circuit 64 having, for example, a variable condenser 65 and a winding 66 of a coupling 67.

The coupling 67 is provided with asecondary winding 70 connected in circuit with the id 19 of a thermionic device 71, having a. usual heated filament. A tuning condenser 72 may be provided in a conventional manner. The output circuit of the device 71 may include a controlled device, such as "a telephone receiver 73. The controlled device may, however, take the form of a solenoid or relay to control a movement or function of a body such as a. torpedo, boat or other object.

A heterodyne shown conventionally as an alternator 80 and a transformer 81 acts on a conductor 82 included in the grid circuits of both devices 56 and 57.

Operation of theheterodyne 80 produces 'an alternating electro-motive force in the conductor 82 and, in co-operation with the oscillations induced in the secondary windings of the transformers and 51, a plurality of series of beats, as will be subsequent 1y set forth.

It is obvious that the tuning condensers 54, and 72 may be omitted without seriously affecting the operation of the system.

In the operation of the system described, the sending station is constructed to impress upon the ether two series of continuous waves of different radio frequencies. The frequencies will be hereinafter designated A 1 and A 2 respectively. The waves are modulated at the sending station by currents of frequencies (B 1 and B 2) less than their wave frequencies. The receiving loops 10 and 11 and the associated circuits 12 and 15 are tuned respectively to the frequencies,-

A 1 and A 2.

The thermionic devices 14 and 17, acting as detectors, (produce in their output circuits superimpose currents having frequencies corresponding to the modulating frequencies employed at the sending station. The two resonant circuits 40 and 41, which are tuned respectively to these modulating frequencies, transmit currents of substantially these frequencies only. The heterodyne 80, 81 is adjusted to produce an alternating electromotive force having a fre uency such that it roduces equal heat requencies with modulating frequencies B 1 and B 2. These beats control the devices 56 and 57 respec-' tively, and there are produced in the output circuits thereof, including the windings 60 and 61 of the transformer 62, superimposed currents of this last named beat frequency. This beat current is induced into the circuit of the indicating device or magnet 73. Circuit 64 is resonant to the beat frequency. The electron device 71 may act as an amplifier when an alternating current device such as a telephone receiver 73 is used or as a rectifier when the device 73 is a solenoid, .or other direct current device.

While an desired frequencies may be employed w ich fulfill the above enumerated requirements, I will cite as examples which may be employed for telegraphic messages the following: 1

A 1; 500,000 cycles per second. t

A 2; 200,000 cycles per second.

B 1; 18,000 cycles per second.

B 2; 20,000 cycles per second.

Heterodyne 19,000 cycles per second.

Beat 1,000 cycles per second. 7

Thus it will e seen'that a message may be transmitted by suitablymodifying, as by interrupting, or otherwise modulating the currents of frequencies, B 1 and B 2, these currents thus acting as so-called carriers. Since two independent carriers are employed,each producing independently a beat current, the message appears in the output or indicating circuit, even though outside interference or other difliculty has rendered one of the channels temporarily inoperative.

If desired, in the use of the system the message may be broken up into several illegible parts, each so chaotic that it cannot be understood. For example, if the message be telegraphic, the dots may be sent over one channel and the dashes over the other. Illegitimate listening in would not then result in revealing) the true messa e, as neither channel could e understood a one.

While I have shown and described'one of the forms in which the invention may be practiced, and given by way. of example values for the requencies which may be employed, it is to be understood that the scope of the invention is not to be determined thereby, reference being had to the appended claims for that purpose. For example, the modulating frequencies, B 1 and B 2, may be equal: in the example cited B l=20,000 cycles per second.

What is claimed is:

1. A system for the transmission of intelligence by radiant energy, comprising a plurality of channels for receiving the radiant energy independently of each other, said channels including a corresponding plurality of receiving devices tuned to frequencies differing from each other by a predetermined amount, and heterodyne means for producing with oscillations of said frequencies a pluralit of series of beats of substantially equa frequencies.

2. A system for the transmission of intelligence b I plurality 0 receiving channels selectively responsive to different portions of said en ergy, said channels including 1!. correspondmg plurality of receiving circuits tuned to fre uencies differing from each other by a pro etermined amount, heterodyne means or producing with oscillations set 11 radiant energy, comprising a said channels a pluralit 0f series of ats of substantially equal requencies, and an indicating device connected with saidqchan nels.

8. A system for the transmission 'pf in telligence 'b radiant energy, comprising a pluralit 0 channels for receiving a message m ependently of'each other one. plurality of series of waves differing in a frequency characteristic, said channels including a corresponding plurality of receivin circuits tuned to different frequencies, an

means for producing current of lower frequency from each of said series of waves,

heterodyne means for producing with said.

currents a corresponding plurality of series of beats of substantially equalfrequencies and an indicating device connected to sai channels and responsive. tooscillations having the frequency of said beats.

4. In a system for the transmission of a message through the ether, a plurality of channels for inde endently recelving a plurality of series 0 waves of different radio frequencies, said channels including receiving circuits exposed and responsive to the ether waves and tuned to their different frequencies respectively and means cooperatively associated with each of said circuits for producing current of lower frequency from the waves received thereby, and heterodyne means for producing with the respective currents a plurality of series of beats of substantially equal frequency.

5. .In a system for the transmission of a message through the ether, a plurality of channels for independently receiving a message from the ether on a plurality of series of waves of different radio frequencies, each of said channels including a receiving circuit arranged to be responsive to ether waves and tuned to one of said difl'erent wave frequencies and means cooperatively associated with said circuit for producing current of lower frequency from the waves received thereby, heterodyne means for producing with said currents a corresponding plurality of series of beats of substantially equal fre:

quencies, and an indicating device connected w1th sald channels.

6. In a system for the-transmission of a message through the ether, a plurality of channels for independently receivin the message from the ether on a plurahty of series of waves differing in a frequency characteristic, said channels including means for producing currents of different frequencies from the respective series of waves and receiving circuits tuned to said different frequencies, means for producing w1th said currents a corresponding plurality of series:

of beats of substantially equal frequencies, a circuit selectively responsiveto the frequency of said beats, and an indicating device controlled by said last-mentioned circuit.

7. In a system for the transmission of a message through the ether, a plurality of channels for independently receiving the message from the ether on a plurality of series of waves differing in a frequency characteristic, said channels including means for producing currents of different frequencies from the respective series of waves, heterodyne means for producing with said currents a correspon ing plurality of series of beats of substantially equal frequencies an indicating device res ons ive to currents of the frequency of ear beats, -.and means for selectively transmitting osc11lat1ons having the ether a and an indicating device responsive to currents of the frequency of said beats.

9. In a system for the transmission of a message through the ether, a plurality of differently tuned channels for independently receiving from the ether a plurahty of series of high frequency waves modulated at different secondary frequencies, means in each of said channels for detecting the en ergy received thereby to produce current of the respective secondary frequency, bet-- erodyne means for producing with the currents from said channels a corresponding plurality of series of beats of substantially equal frequencies, said means including a network independently coupled to .each of said channels, and an indicating device connected with said network.

10. In a system for the transmission o'fla message through the ether, a pluralit '-'of channels for lndependently receiving rom ondary frequencies, means in each of the channels; for detecting the energy "received; thereby to produce current of the respective secondary frequency, receiving circuits in the ether a plurality of series of high-ire- 1 quency waves modulated at diiferent'sec the channels tuned to the secondary frequencies respectively, heterodyne meansfor producing with the currents from said channels a corresponding plurality of series of,

beats of substantially equal frequencies, and

an indicating device connected with the channels.

' 11. Ina system for the transmissionof'a messagethrough the ether, a plurality of channels. for independently receiving from plurality of series of waves of dlfierent radio frequencies, each modulatedat a secondary frequency, circuits responsive y to the waves included in said channels respectively and tuned to said different radio frequencies, means cooperativel with each of said circuits for etecting the energy received thereby to roduce' current of the corresponding secon ary fre uency, heterodyne means for producing w1th the currents from said channels a corresponding plurality of series of beats of substantially 7 equal frequencies, and an indicating device connected to said producing means and said channels.

associated 12. In a system for the transmission of a message through the ether, a pluralityt of cm channels for inde endently receiving the ether a plura ity of. series of waves of different wave frequencies modulated at different secondary frequencies respectively, a plurality of circuits included in each of said channels and tuned respectively to one of said wave frequencies and one of said sec ondary frequencies, means in each of said channels beween said circuits for detecting the energy received thereby to produce current of the corresponding secondar frequency, heterodyne means for pro ucing with the currents from said channels a correspondin plurality. of series of beats of substantia y equal frequencies, and an indicating devices-connected to said producing means and said channels.

, 13. In a system for the transmission of a message through the ether on a plurality of substantially equal fre uencies.

j 14. In a system for t e transmission of a message through the ether on a plurality of 'serigw of waves, a receiving arrangement comprisin a plurality of independent channelsiinclu ing difierently. tuned circuits, .an i indicating device andimeans for. transmitt' current from said channels to the indicatingdevice, said means comprising a heterodyne" for convertin currents from said channelsainto audio requency currents of substantially equal frequencies'and an oscillatory circuit tuned to a said last-mentioned frequency.

15. A method of communicating al'mes:

edge by radiant energy which'eonsists in transmitting apluralit of series of high fre uency wavesmod ated in accordance .wit the message, receiving said pluralit of series of waves in separate rece1v1n c annels, producing in said receivin c annels from said plurality of series 0 waves a correspondin plurality of series of currents of difierentfrequencies respectively, heterodyning said currents toproduce therefrom a plurality of series of beats ofsubstantially equal frequencies and controlling a single indicating device by said plurality of series of beats. v I

16. A method of communication by radiant energy which consists-in transmitting a plurality of series ofhigh fr uency waves of difierent wave frequencies aving periodic variations of different frequencies respectively and all modulated in accordance with the message, receiving the pluralit of series of waves indifierent receiving 0 annels, detecting the series of waves in the respective receiving channels to produce currents having the frequencies of the variations respectively, heterodyning said currents to produce a plurality of series of beats of substantially equal frequencies, and controlling a single 1ndicating device by said of series of beats.

17 T e method of communicating a message by radiant energy which consists in transmitting two series of high fnequenc waves, each modulated in accordance with the entire message, receivin the two series ofwaves 1n difierently tune receiving channels, roducing in said channels two currents modu ated in accordance with the modulations of thetransmitted waves, heterodyning the currents to produce two series 'of beats of substantially equal frequencies and impressing both of said series of beats on a common indicatin device.

'In testimony-w ereof I hereunto afiixed my signatures nmoagr LEON CHAFFEE.