US1463386A - Radiotelegraph system - Google Patents

Description

July 31, 1923. 1,463,386

w. l.. CARLSON E T Al.

RADIO TELEGRAPH SYSTEM Filed April -22 1920 5 Sheets-Sheet l MWI".

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July 31, 15523.

1,463,386 W. L. CARLSON ET AL RADIOy TELEGRAPH SYSTEM Filed April 22, 1920 3 Sheets-Sheet 2 Invenow July 31, 1923. 1,463,386

W. L. CARLSON ET AL RADI O TELEGRAPH SYSTEM Filed April 22. 1920 3 Sheets-Sheet 3 @www Patented Jury si, i923.

PATENT GFFICE.

WINDELL L. CARLSON AIND EARL C. HANSON, F WASHINGTON, DISTRICT 0l' OOLUIBIA..

i BADIOTELEGBAPH SYSTEM.

Application led April 22,

To all 'whom it may concern:

Be it known that we, WENDELL L. 'CARL- soN and EARL C. Hanson, citizens of tne United States, residing at Washington,

I District of Columbia, have invented certain new and useful Improvements in Radiotelegraph Systems, of which the following is a specification.

This invention relates to the reception of l0 radio or wireless signals and more particularly to those systems employing sustained wave reception. i

The primary object of our invention is to provide an electric circuit for selectively receiving electric signals.

A further object is to provide an electric circuit for selectively recording electric signals on a permanent recording device and selectively reproducing said recorded signals, so as to actuate a responsive device. O

The invention is illustrated diagrammatically in two of its forms in the accompanyin drawings, wherein- Figure 1 shows a receiving ap aratus for zu selectively recording received ra io signals;

and

Figure 2 shows apparatus for selectively re roducing received signals in Figure 1.

igure 3 shows receiving apparatus for sea0 lectively receiving radio signals.

Referring particularly to the diagram shown in Figure 1 reference character 1 represents a tuned antenna circuit coupled to a tuned secondary circuit 2. The secondary 85 circuit 2 is connected t0 the multistage high power amplifier comprising the thermionic vacuum tubes 3, 5 and 7, the tuned radio frequency transformer 4 having a natural period of approximately the same wave length as the `signal energy to be received and the audio frequency transformer 6. Condenser 8 shunted by the `usual grid leak, is inserted in the grid circuit of the detector tube 5.

The telegraphone recorder 10 comprises the electromagnets 9 and the moving steel wire 11, which is operated by reel mechanism 12. Motor 13 drives reel mechanism 12 by means of the extended shaft 14.

The vacuum tube generator 18 is loosely coupled to the tuned circuit 2.

In Figure 2 the electromagnets 9 are connected to the input of an amplifier comprising tuned audio frequency transformer 15 1920. Serial No. $75,688.

designed for maximum efficiency at the particular frequency employed and thermionic tube 16. The output of the amplifier is connected to an audio frequency responsive device 17.

In Figure 3 the audio-radio frequency amplifier shown in Figure 1 has its output connected to the electromagnets 19, which partially surround magnetic rotor 21. Electromagnets 22 are connected through audio frequency transformer 15 to vacuum tube 16. The output of vacuum tube 16 is connected to the signal responsive device 17. The electromagnets 23 are energizedby the batterv 24.

The operation of the system is as follows: The radio frequency circuits 1 and 2, Figure 1, are definitely tuned to the frequency of the incoming radio si nal. The thermionic vacuum tube 2 amp ies the received radio frequency energy and imprees said energy on the grid circuit of the detector tube 5 through the radio fre uency transformer 4. The energy from tlie oscillating tube generator 18 is also impressed on the grid circuit 0f the detector tube 5. Said oscillating energy is of a frequency differing by 500 cycles from the frequency of the incoming signal. The resulting heterodyne b'eat of 500 cycles is transferred to the audio frequency amplifying tube 7, by means of the audio frequency transformer 6. The output energy of the vacuum tube 7 energizes a plurality of electromagnets 9, which are arranged in a row along the path of the moving steel wire 11.

The individual sets of windings function similar to the well known talking heads in the usual telegraphone.

One of the important, factors to be considered in this invention is to have the physical distance between adjacent electromagnets equal to, or in multiple of the physical distance between magnetic stresses applied to the moving steel wire by the action of the incoming signal. The polarity of adjacent electromagnets must be alternately reversed if they are to act on the moving steel wire at distances from each other, corresponding to 1%, 2%, etc. cycles. (Considerin cycle as corresponding to the linear lengt of localized charge, placed on the wire by cycle incoming audio frequency currentl The polarity of the electromagnets shown in the drawing are indicated to agree with the above condition.

The polarity of adjacent electromagnets must be identical if they are to act on the moving steel wire at distances from each other corresponding to 1, 2, 3 and etc. cycles.

The linear dimensions of the space magnetic stress develo ed on the steel wire, will be determined by t e frequency of the signal recorded and the speed of the steel wire. For example, if the beat si nal to be recorded is adjusted to 500 cyc es and the steel Wire is moving at the rate of 125 inches per second, then the ad'jacent electromagnets must be physically adjusted so. that their magnetic fields will act on the wire at space distances of i, il, etc. inches from each other, depending on the polarity of adjacent electromagnets and the physical limitations of the electromagnet construction.

Any arrangement of electromagnets may be employed, which will allow for the synchronizin 0f the three variable factors mentione above, namely, 1st, frequency of the signal which it is desired to record, 2nd, distance between adjacent electromagnets and 3rd, linear speed of the moving element on which the signal is to be recorded.

It will be understood that if an interfering signal of, for example, 800 cycles is impressed on the electromagnets, that the phase relation of the various factors will not permit the signal energy localized on the steel wire by one set of clectromagnets, to synchronize with the electromagnetic field produced by the adjacent set of electromagnets, when said localized signal energy passes under the influence of the said adjacent electromagnets. A decrease in strength of signal recorded will, therefore, result.

A 500 cycle signal, for which the apparatus is adjusted to receive, will be recorded with increased intensity, because each set of electromagnets will strengthen the localized signal energy on the steel wire as it moves in synchronism past adjacent electromagnetic fields.

In the practical operation of the apparatus, the elcctromagnets may be designed to have either open or closed magnetic iron cores. Successive electromagnets may, if desired, be designed to have a decreasing magnetic effect on the steel wire by employing a fewer number of turns of wire, or by lengthening the air gap in the iron core.

In order that the speed of the moving steel wire may remain constant, any suitable means may be employed for automatically regulating the speed of the driving motor to compensate for the constantly varying diameter of the reels 12, due to the unreeling of the steel wire wound thereon.

To eliminate inductive interference, caused by the driving motor 13, it is advantageous to place the drivin motor a few feet away from the telegrap one apparatus and connect by shaft.

In Fi ure 2 the reproducing process is the reverse uplication of the recording process in so far as the telegraphone apparatus is concerned. Additional selectivity being obtained as in the recordin process. The cycle signal energy, derived from the telegraphone, actuates the audio frequency re ceiving device 17, by means of the vacuum tube amplifier circuit, comprising the audio frequency transformer 15 and thermionic vacuum tube 16.

In Figure 3 the signal energy impressed on the electromagnets 19 is derived from a source similar to that previously described in Figure 1.

The local external oscillating vacuum tube enerator 18 of Figure 1, is not shown in `igure 3, but may be employed, if the radio frequency circuit including tube 3 is not adjusted to produce local oscillations to autodyne with the incoming signal producing the required audio beat note.

The rotating disc 21 in Figure 3, is substituted for the moving steel wire l1 in the telegraphone 10, shown in Figures 1 and 2. The signal energy is recorded on the rotating disc 21 and as the disc rotates past the electromagnets 22, the localized energy recorded on the disc 21 actuates the electromagnets 22 in a manner similar to the process wherein the energy on the steel wire in Figure 2 actuates the electromagnets 9. 100 The 4responsive device 17, in Figure 3, is eventually acted upon in like manner to the process of actuating the responsive device 17 in Figure 2.

The electromagnets 23, energized by the 105 battery 24, are employed to erase the localized magnetic signal energy recorded on the revolving disc 21, after said disc has passed the electromagnets 22. The rotating disc may be constructed of laminated steel.

It will be understood that we are not to be restricted to the specific structure of the apparatus shown herein.

What we claim is:

1. In a system of radio telegraphic recep- 115 tion means for receiving signals of a predetermined frequenc a telegraphone, a re cording element t erefor, a. plurality of electromagnets associated therewith and spaced apart in proportion to the frequency 12" of the signals to be received and the linear speed of the recording element.

2.. In a system of radio telegraphic reception means for selectively receiving energy of a. particular frequency comprising a 125 te egraphone having a recording element, a multiple set of magnets associated therewith and connected in the receiving circuit, said magnets being spaced apart in proportion to the frequency of the signals to be ren" ceived, and the linear speed of the recording element.

3. In a system of radio telegraphic reception means for selectively receiving energy A of a articular frequency comprising a telegrap one having a recording element, a plu` rality of magnets connected in series and arranged to be synchronousl energized by the received energ in accor ance with the speed of the recor ing element, the spacin of said magnets and the frequency of sai signal, and a reproducing circuit for selective translation of the recorded signals.

4. In a system of radio telegraphic reception the combination of a circuit adjusted to respond to signals of a definite audio freuency a tele aphone having a recording' e ement whichgi; unwound from one reel an continuously stored in bulk on another reel and means 1n said circuit for integrating en- 20 raphone wire elementl a circuit energized al y the received signals including a plurality of sets of multiple electro magnets received in series and adjusted in relation to said wire element to respond to the frequency of said signals.

WENDELL L. CARLSON. EARL C. HANSON.

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