US1865171A - Apparatus for recording and reproducing sound - Google Patents

Description

.June 28, E c p 1,865,171

APPARATUS FOR RECORDING AND REPRODUCING SOUND Filed May 5, 1928 2 Sheets-Sheet l 5+ c- 6+ c- C+ 67 4.5 9 40 gvwemtoz M 8, wa

WMWQLM- June 28, 1932. CHIPMAN 1,865,171

APPARATUS FOR RECORDING AND REPRODUCING SOUND Filed May 5, 1928 2 Sheets-Sheet 2 awuemtoz Ill for reproducing purposes.

. faithfully reproduced.

Patented June 28, 1932 UNITED STATES PATENT OFFICE HARRY E. CHIPMAN, OF SPRINGFIELD, MASSACHUSETTS, ASSIGNOR, BY DIRECT AND MESNE ASSIGNMENTS, TO ANDREW LE ROY CHIPMAN, OF NEW YORK, N. Y.

APPARATUS FOR RECORDING AND REPRODUCING SOUND Application filed May 3, 1928. Serial No. 274,775.

This invention relates generally to an apparatus for recording and reproducing sound, and more particularly to an apparatus adapted to receive radio waves, permanently record, on a wire, magnetic impressions derived from either radio waves or sound waves, and reproduce from the magnetic impressions, however received, 1mpressed upon the wire, sounds of audible form broadcast through the output end of the radio receiving apparatus.

A need has arisen for some reasonably cheap and effective means by which an individual can permanently record the choicer and more appealing radio programs, and reproduce them at any time thereafter. An object of this invention, therefore, is to provide an apparatus by means of which radio waves may be received and the sound characteristics thereof permanently recorded Another object of this invention is to provide an apparatus by means of which the characteristics of all sounds may be permanently recorded and Another object of this invention is to devise an apparatus by means of which recorded sound impressions, obtained by radio or otherwise, may be reproduced and broadcast through the output end of my radio receiving apparatus.

Other objects of this invention will become obvious as the disclosure proceeds.

In order that a clearer understanding of my invention may be had, attention is hereby directed to the accompanying drawings,

forming a part of this application and illustrating certain possible embodiments of this invention.

Referring to the drawings, Fig. 1 is a diagrammatical view of a portion of the apparatus, more particularlythat portion of the apparatus operative to receive radio waves and transform them into a pulsating current of audio frequency; and I Fig. 2 is a diagrammatical view of that portion of the apparatus adapted to permanently record either the characteristics-of sounds directly or the characteristics of the pulsating radio waves, including means for translating the recorded soundor current characteristics into such a form as to be reproducible from the loud speaker of the radio receiving apparatus.

Referring to Fig. 1 of the drawings, radio frequency energy received upon the antenna 1 of any desired characteristics is directed through the transformer 2, comprising the usual primary and secondary windings, through wire 3 to ground at 4:. The energy transferred to the secondary winding leaves the transformer 2 through terminal 5, and is directed through a grid resistor 6 to the grid electrode of a three electrode vacuum tube 9. The frequency of the received si nal may be controlled by the usual tuning means, such as has been conventionally illustrated by the variable capacity condenser 7 shunting the secondary of the transformer. In parallel'with the condenser 7 I have placed a small capacity condenser 8, which may serve as a Vernier to establish fine tuning.

Output energy leaves the plate of vacuum tube 9, passes through conductor 10 and through the primary winding of transformer 11. Energy transferred to the secondary Winding of transformer 11 leaves the transformer through terminal 12, and is directed through the usual grid resistor 13 to the grid electrode of vacuum tube 14. The usual tuning condenser 15 is associated with the secondary of transformer 11. A small capacity condenser 16 is connected between the primary and secondary windings of transformer 11 for the purpose of neutralization.

Output energy from the plate of vacuum tube 14 passes through conductor 17 and through the primary winding of transformer 18. Energy transferred to the secondary winding leaves the transformer 18 through terminal 19, and is directed to the grid electrode of vacuum detector tube 20 through a grid resistor 21 and associated grid leak and condenser 22. Tuning condenser 23 is associated with transformer 18 in the conventional manner. The output terminals of primary windings of transformersll and 18 are connected to the positive terminal of a B battery through conductor 24 and variable resistance 25. The secondary windings of transformers 2, 11 and 18 may be connected together by a conductor 26 and suitably grounded, as at 27, 28 and 29.

\Vhen a switch arm 30 is thrown, so as to connect together contact points 31 and 32 and contact points 33 and 34 current flows from the A battery and conductor 35, through a conductor 36, and through the filament circuits of vacuum tubes 9, 14 and 20. Appropriate resistances of either a fixed or variable nature, as resistances 37, 38 and 39 may be inserted in the filament circuits to control the filament voltage.

When contact points 31 and 32 are connected by switch arm 30, output energy from the plate of vacuum detector tube 20 passes through conductor 40, through conductor 41 and through the primary winding 42 of an audio transformer 43. Energy induced into the secondary winding 44 of transformer 43 is then directed through conductor 45 to the grid electrode of audio amplifier tube 46. Energy leaves the plate electrode of tube 46 through conductor 47 and passes through the primary winding 48 of a second transformer 49. The primary windings 42 and 48 are connected by means of conductors 50 and 51 to a B battery through choke coil 52, the B battery serving as a source of plate potential for detector tube 20 and audio tube 46. A con duetor 53 connects the plate electrode of detector tube 20 through a small condenser 54 to the negative terminal of the A battery.

Energy transferred to the secondary winding 55 of transformer 49 is directed through a potentiometer 56 arranged to control the potential on the grid of audio tube 57. Output energy from the plate electrode of tube 57 is directed through conductor 58 to out put terminal 59 of the receiving system after first passing through a filter comprising shunt inductance 60 and series capacity 61.

The secondary windings of transformers 43 and 49 are connected by conductors 62 and 63 tothe terminals of C batteries in a conventional manner.

When switch 64 is closed, current constantly flows through the filament circuits of audio tubes 46 and 57, and they remain lighted. A small condenser 65 of 4 microfarad capacity may be shunted between the terminal of the A and B battery, in the convent-ionaLmanner, to obtain finer control over the current flow. One output terminal 66 of the receiving system is connected through conductor 67 to a B battery, and the other output terminal 59 is connected to the plate electrode of vacuum tube 57, as already explained.

When contact points 31 and 32, 33 and 34 are connected, it is seen that there is presented a complete radio apparatus operative to receive radio waves and to translate them into apulsating current of audio frequency output through output terminals 59 and 66.

My recording device, illustrated diagrammatically in Fig. 2, operates to impress upon and 69, which are plugged into the output terminals 59 and 66 of the radio receiving apparatus. The pulsating current of audio frequency from plugs 68 and 69 is directed to the secondary winding 70 0f a transformer T1, bearing a two to one ratio, through conductors 72 and 73. Energy induced into the primary winding 74 of the transformer is direct-ed to the secondary winding 7 5 of a sec ond transformer 76, of approximately fourteen to one ratio, through conductors 77 and 78. One end of the primary winding 79 of transformer 76 is connected to two plugs 80 and 81 through conductors 82 and 83, and the other end of primary winding 79 is connected to plug 84 through conductor 85. Although one transformer can be used in place of the two transformers 71 and 76, much better recording results are obtained by the use of two transformers connected as above outlined.

I have represented my recording head con taining the electromagnets for magnetizing the wire diagrammatically at 100; the structure of my recording head having been disclosed in my prior Patents No. 1,612,359 and Reissue No. 16,586, and forms no part of this invention. The recording head is provided with an upper and a lower electromagnet, each provided with a primary and secondary winding, each secondary winding having many more turns than the corresponding primary winding. When plugs 80 and 84 are placed in their corresponding sockets 86 and 87, the pulsatin current, induced into primary winding 79, flows from terminal 87 through conductor 88, through primary winding 89 of an induction coil 90, preferably of the closed core type, through conductor 91, through the battery K, and thence through conductor 92 to socket terminal 86. Conductor 91 also connects to a resistance R, the other side of which is connected by conductors 93 and 94 through binding post 95 to the primary 96 of the erasing and polarizing coil. The negative terminal of battery K is connected by conductor 92, through sockets 86 and 97 to conductors 98, 99 and 101 to the primary winding 102 of the upper recordingelectromagnet 103 of recording head 100. Primary win-ding 102 is connected to the primary winding 104 of lower recording magnet 105. to conductor 106, to primary winding 107 of lower erasing and polarizing magnet 108, and to primary winding 96 of upper erasing and polarizing magnet 109 of erasing and polarizing head 110. Thus it is seen that a uniform direct current flows from the positive side of battery K through primary windings 96 and 107 of upper and lower erasing and polarizing magnets 109 and 108, and thence through primary windings 104 and 102 of lower and upper recording magnets 105 and 103 back to the negative side of battery K. The current flow may be controlled by the variable resistance R.

The pulsating audio frequency current induced into the secondary winding 111 of induction coil 90 is directed through conductors 98, 99 and 101 through the secondary winding 112 of upper recording magnet 102 through the secondary 113 of lower recording magnet 105, through conductor 114 and back to the secondary winding, forming a complete electric circuit for the pulsating current.

The pulsating current in the secondary windings 112 and 113 inducessimilar pulsations in the direct current flowing through primary windings 102 and 104 of the upper and lower recording heads. As a result, the cores of the recording electromagnets 103 and 105 will be magnetized with an intensity which varies at each moment in accordance with the fluctuations of the current in circuit 98 and 114. A metal ribbon or wire passing between the core pieces of upper and lower magnets 103 and 105 will have corresponding variations of magnetic intensity impressed thereon. The wire passing through the recording -head 100 will thus be magnetized in the desired manner, and a magnetic sound record of the program received over the radio will be impressed thereon. Erasing magnets 108 and 109 are for the purpose of removing any magnetism already in the wire before it enters the recording head, as explained in my prior patents above referred to. Upper and lower electromagnets 103 and 105 constituting the recording head 100 are so wound as to develop an impedance of approximately 50 ohms, while the upper and lower magnets 109 and 108 of erasing and polarizing head 110 are so wound as to develop an impedance of approximately 17 ohms.

It is seen that in recording sound, no current flows through the secondary windings 115 and 116 of the upper and lower windings of the erasing and polarizing head 110. Current flows, however, through the primary coils 96 and 107 of the erasing and polarizing head 110 which operate to uniformly magnetize the core pieces within these primary coils. Since the wire first passes through the erasing and polarizing head 110, any magnet-ism that may be in the wire is neutralized and the Wire given a uniform polarity by the core pieces within the upper and lower primary coils 96 and 107. The wire, with the magnetic sound record of the radio program impressed there on, may be wound upon a spool and stored for future reproduction on my apparatus, as will now be described.

Head 100 is used as a part of the reproduc- 113. This fluctuating current is directed to sockets 118 and 12 1 through conductors 99 and 122 and through conductors 125 and 126 and binding post 127.

The magnetized sound recording wire is generally run through both heads 110 and 100 and by so doing the fluctuating current strength can be increased with corresponding increased volume of the reproduced sound. Considering head 110 as also a part of the reproducing unit, when the magnetic material carrying a magnetic sound record is progressed between the pole pieces of the upper and lower electromagnets 109 and 108, an electric current which fluctuates in accordance with the variations of magnetic intensity in the magnetized material will be induced in the secondary windings 115 and 116 of the upper and lower electromagnets 109 and 108. This pulsating or fluctuating current induced in the secondary windings isdirected to sockets 117 and 118 through conductors 119 and 120 and binding post 121 and through conductors 99 and 122 and binding post 123. It is seen that when both heads 110 and 100 are used, the induced current flowing from secondary winding 115 of head 100 passes into conductor 99 where it is joined or added to the induced current from the secondary winding 102 flowing through conductor 101 and also into conductor 99. Although the magnets of heads 110 and 100 are spaced approximately 34 of an inch apart, in actual practise approximately three feet of magnetized wire are required to reproduce, for instance, the sound characteristics of a. It is therefore seen that the interference between the magnets in the respective heads is negligible, and practically they cooperate together to increase the sound volume. All interference can of course be eliminated by using a sufliciently wide sound recording wire or band and placing the magnets on opposite sides of the band.

\Vhen reproducing, the wire carrying the magnetic sound record is therefore preferably run between both pole pieces of heads 110 and 100, as above described. Plugs 128, 129 and 130 are plugged into their respective sockets 117, 118 and 124, and terminals 131 and 1.32 are connected to jack terminals 133 and 134. Switch handle 30 is thrown so as to connect terminal 135 with 136 and terminal 137 with 138. The pulsating direct current of audio frequency is thus directed to the jack terminals 133 and 134, one of which is connected with a source of filament potential through conductor 139. The other terminal 133 of the jack is connected through conductor 140 to the grid electrode of a vacuum tube 141, through which the pulsating current produced by the magnetized wire is directed. When terminals 137 and 138 are connected, the filament circuit of tube 141 is closed, current flowing from the positive terminal of the A battery through conductors 35 and 143, through the filament, through conductor 144, through a variable resistance 145, through conductor 139, and back to the negative terminal of the A battery.

Output energy from the plate electrode of tube 141 is then directed through conductor 142 and 146 and through the primary winding 42 of the audio transformer 43. The audio pulses are then transferred, in a manner similar to that described in connection with the reception of *adio frequency energy. by having the amplified energy directed through amplifying audio tubes 46 and 57 and thence to the speaker terminals 59 and 66. It will be noted that when switch 30 is moved to connect terminals 31 and 32, 33 and 34, the detector tube 142 has its plate circuit open. When switch arm 30 is moved to connect terminals 135 and 136, 137 and 138, then the output circuits of detector tube 20 and its associated radio frequency amplifier tubes 9 and 14 are open. The terminals 33 and 34, 137 and 138 open and close the filament circuits, terminals 33 and 34 controlling the filament circuits of amplifier tubes 9 and 14 and detector tube 20, and terminals 137 and 138 control the filament circuit of amplifier tube 141.

If a loud speaker or phones are connected to terminals 59 and 66, with switch 30 moved to cover contact points 31 and 32, 33 and 34, the apparatus may be used as the ordinary radio set for the reception of radio programs.

. With terminals 68 and 69 plugged into sockets 59 and 66, the radio program may be recorded on the wire in the form of a magnetic sound record.

My apparatus is also adapted to record sound other than that received by radio waves. To record any sound, a microphone is plugged into sockets 86, 87 and 97. The wave, characteristics of the sounds secured by the microphone produce fluctuations in the direct current flowing from battery K. This fluctuating current, flowing through primary winding 89 of induction coil 90, induces a corresponding fluctuating current in secondary winding 111. This fluctuating or pulsating current is translated into a magnetic sound record on the wire in the manner already described in connection with the recordation of radio programs.

It is thus seen that I have provided an apparatus by means of which radio programs may be received and permanently recorded, to be later reproduced as desired. Sounds other than those received by radio waves may also be recorded and reproduced by my apparatus in the same manner.

As many changes could be made in the above construction and as many widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

lVhat I claim is 1. Apparatus for recording and reproducing natural sounds, including, in combination, electro-magnetic recording means including an electro-magnet having co-axial primary and secondary windings, a source of direct current connected with said primary winding to flow therethrough, means for converting received radio frequency energy modulating in correspondence with natural sounds into correspondingly modulating audio frequency electric current,means directing said current to flow through the secondary winding of said electromagnet to modulate the intensity of the magnetic field of said magnet in correspondence with the modulations of said current, a magnetizable record carrier, and means for moving said magnetizable record carrier through the field of said magnet to place on said record carrier magnetic impressions modulating therealong in correspondence with said received modulating radio frequency energy, whereby said record carrier is conditioned for magnetic reproduction therefrom of the sounds governing the modulations of said received radio frequency energy. I

2. Apparatus forrecording and reproducing natural sounds, inc1uding,in combination, electro-magnetic recording means including an electro-magnet having co-axial primary and secondary windings, a source of direct current connected with said primary winding to flow therethrough, means for converting received radio frequency energy modulating in correspondence with natural sounds into correspondingly modulating audio frequency electric current, means directing said current to flow through the secondary winding of said electro-magnet to modulate the intensity of the magnetic field of said magnet in correspondence with the modulations of said current, a magnetizable record carrier, means for moving said magnetizable record carrier through the field of said magnet to place on said record carrier magnetic impressions modulating therealong in correspondence with said received modulating radio frequency energy, and means for electromagnetically reproducing from said record carrier soiindscorresponding to the magnetic impressions thereon.

3. Apparatus for recording and reproducing natural sounds, including, in combination, electro-magnetic recording means including an electro-magnet having co-axial primary and secondary windings, a source of direct current connected with said primary winding to flow therethrough, means for C0111 verting received radio frequency energy modulating in correspondence with natural sounds into correspondingly modulating audio frequency electric current, means directing said current to flow through the secondary winding of said electro-magnet to modulate the intensity of the magnetic field of said magnet in correspondence with the modulations of said current, a magnetizable record carrier, means for moving said magnetizable record carrier through the field of said magnet to place on said record carrier magnetic impressions modulating there'along in correspond ence with said received modulating radio frequency energy, and means including said electro-magnet for reproducing from said record carrier sounds corresponding to the magnetic impressions on the carrier.

4. In an apparatus for recording and reproducing sounds, in combination, a radio receiver having an output circuit, a pickup tube havingvan input circuit and an output circuit, an amplifier having an input circuit, and a single switch whereby the output circuit of the radio receiver and the output circuit of the pick-up tube may be selectively connected with the input circuit of the amplifier in accordance with the adjustment of the switch, a telegraphone device, including a recording and reproducing electro-magnet, having primary and secondary windings, a source of current of uniform intensity, means for causing said current to fiow through the primary winding of said electro-magnet to condition the magnet for recording action and a circuit through the secondary winding of said electro-magnet, and means for electrically connecting said circuit through said secondary winding with the output circuit of said amplifier.

5. In an apparatus for recording and reproducing sounds, in combination, a radio receiver having an output circuit, a pick-up tube having an input circuit, and a single switch whereby the output circuit of the radio receiver and the output circuit of the pick-up tube may be selectively connected with the input circuit of the amplifier in accordance with the adjustment of the switch, a telegraphone device, including a recording and reproducing electro-magnet, having primary and secondary windings, a source of current of uniform intensity, means for causing said current to flow through the primary winding of said electro-magnet to condition the magnet for recording action and a circuit through the secondary winding of said electro-magnet, and means whereby said circuit through said secondary winding may be connected selectively with the output circuit of received radio broadcast; a circuit including 7 the microphone, audio frequency amplifier and telegraphone head for telegraphonic recording of audible sounds; and a circuit including the telegraphone head, pick up tube, audio frequency amplifier and loud speaker for audible telegraphonic reproduction.

, This specification signed this 28th day of April, 1928.

HARRY E. CHIPMAN.

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