US1722940A - Method and apparatus for transmitting written characters - Google Patents

Description

H. PEIN July 30, 1929.

METHOD AND APPARATUS FOR TRANSMITTING WRITTEN CHARACTERS Original. Filed Sept. 29. 1925 Patented July 30, 1929.

HEINZ IPEIN, OF BREMEN, QEBMANY.

METHOD AND APPARATUS FOR TRANSMITTING WRITTEN CHARACTERS.

Original application filed September 29, 1925, Serial No.

Divided and this application filed November This invention relates to a method and an apparatus for transmitting written characters of that class in which control-members are used in the transmitter for produc- 5 ing fluctuations of electric energy in accordance with the path of curves which are obtained from the resolving of the curvelines of written characters into their components, whereas in the receiver the characters from which the said component curves are obtained are recomposed by the transmitted fluctuations of electric energy, as I more particularly described in my Patent N 0. 1,715,781, June 4, 1929 (Serial No. 59,410, tile-d September 29th, 1925).

The object of my present invention is to facilitate the provision of the control members'by multiplying them photographi(rally. Another object of the invention consists 2 in that the current fluctuations are not only accommodated to the shape of the curves, but also that certain frequencies can be impressed upon them so as to render it possi ble to superpose several frequencies upon a main wave.

According to my invention meansfor producing fluctuations of light, for instance light-filtering bands, are used as controlmembers, which fluctuations of light are in accordance with the path of the component curves. The fluctuations of light influence the resistance of cells sensitive to light, which are inserted in the transmitting circuits so that fluctuations of electric energy according to the component curves are effective in the transmitting device.

The invention is illustrated diagrammatically and by way of example in the accompanying drawings.

ig. 1 is a perspective illustration of a .device for the photoelectric transmission of the curves of written characters,- Figure 2 shows' a modification of the ray guiding parts of Fig. 1 for the simultaneous transmission of two curves of written characters and a receiving apparatus for reeomposing the transmitted character;rFig. 3 shows a component-curve obtained from the decomposition of a written character; Figures 4, 5 and 6 show three forms on an enlarged scale of the light-filtering band used in the apparatus; Fig. 7 shows a portion of the light-filtering band of Fig. 6 on an enlarged 7 scale; and Figures 8 and 9 illustrate dia- 55 grammatically an arrangement wherein a 59,410, and in Germany February 16, 1925.

18, 1927. Serial No. 234,250.

plurality of frequencies can be superpositioned upon the wave transmitted, and whereby the respective frequencies can be caused to act upon the writing member of the receiving station by means of resonators.

Referring now to Figs. 1 and 2, a source of light 88 is provided for the photographic transmission of the coordinate curves; the light passing in parallel rays through a lens 89 and being directed on a light-screen 90 provided with a slot 91 so that only a strip 92 of the light pencil can pass through that slot. The strip of light falls upon a band or tape 93 provided with perforations 94:; the distance between the individual perforations and the edge of the band corresponding always to a distinct character, in consequence whercof the perforations pertaining to equal characters lie vertically one below the other. Vhen the strip of light falls upon a perforation 94, a ray of light 95 is thereby separated from that strip and falls upon a certain portion of the circumference of the cylinder 96.

It is advisable to provide a system of lenses (not shown) between the perforated band 93 and the cylinder 96 in order to so modulate the ray of light that it falls upon the cylinder with a great intensity, but only in a narrow breadth. The cylinder may consist of a transparent material, as glass or the like. Upon its surface lightfiltering strips 97, 97, 97" are provided each of which is equivalent to a component curve of a character; each band is allotted 90 to an individual perforation and'is more or less transparent in correspondence with a component curve of the respective character its perforation represents.

Owing to this provision, the ray of light 95 penetrates with a greater or lesser intensity into the interior of the cylinder 96 where there is provided a parabolic mirror 96 that reflects, by reason of-its shape, all rays falling upon it to the cell 87 which is 100 sensitive to light and is more or less excited by the various rays. As the cell 87, for instance a selenium cell, responds to the intensity of the rays falling upon it, the currentfluctuations necessary to transmit the Writ- 105 ten characters according to this invention are produced.

The cylinder 96 is rotated by appropriate means, for instance, a worm 80 and a wormwheel 81, so that the entering ray of light 110 wheel 102 is turned. The chain wheel is connected to and rotates a drum over which the band 93 passes. Thus the perforated band is moved only during that period of time between the illumination of two lightfiltering bands, but is stationary when the illumination takes place.

In order to provide for a shockless transition of the rays of light from a lightfiltering band 97 to another light filtering band 97 the cylinder is, preferably, rendered transparent in a degree corresponding I to the mean transparency to light of the light-filtering bands at those portions which are not covered by each band. For transmitting the two component curves (abcissaand ordinate-curve) of a written character two devices of the kind shown in Fig. 1 are necessary.

Referring now to Fig. 2, this figure shows the use of a source of light for the simultaneous illumination of two cells 87" and To attain this, the light screen 90 is provided with two slots 91 and 91*" so that twoseparate strips of light 92 and 92* fall upon the perforated band 93 shown in cross-section in Fig. 2. This band is provided with two corresponding rows of perforations sifting out the rays of light 95 and 95*" which then pass through light-filtering bands similar to the bands 97, 97 (Fig. 1) into the interior of the cylinder 96, where there are provided mirrors 97 and 97 at the two sides of a partition wall 103. These mirrors reflect the rays of light to the cells 87 and 87" which are sensitive to light, as described.

With this constructional form there are always two cells influenced by two corresponding rows of perforation of a band, whereby the two curves requisite to produce a written character are transmitted synchronously.

Instead of sifting out two rays of light by two corresponding perforations of the perforated band, only one ray may be sifted out by one perforation, divided into two rays by reflection or an equivalent procedure and each ray is projected onto filtering bands representing the component curves of a character; these two filtered rays being then used in the manner above described.

According to the varying resistance of the cells 87 and 87*" current fluctuations are produced, which by the circuits 1 and 2 are carried to the receiving apparatus. In the receiver magnet coils67, 67 are inserted in the circuits 1, 2, which coils act upon an armature 68 supporting a writing member 4. If the two coils are simultaneously magnetized according to the component-curves of a character, the motion of the armature 68 is the resultant of the component-curves, so that the writing member writes the transmitted character on the paper-tape 34, which is fed forward by any suitable feeding de vice (not shown).

The light-filtering bands shown in Fig. 1 may be produced in several ways. In Figs. 4c, 5 and 6 three diaphragms are. shown which all correspond to the curve a) (Fig. 3), and are more or less permeable to light according to this curve. The varying per meability or transparency to light of the constructional form shown in Fig. 4 and dcnoted by the numeral 97oz is attained by the larger or smaller width of a slot 104 which is being moved along in front of the ray of light like a diaphragm. But the varying permeability or transparency can be brought about by the judicious toning of the bands in conformity with the curves (such as m, Fig. 3).

In Fig. 5 97,8 denotes a band of this kind. The third constructional form illustrated in Figs. 6 and 7 is characterized by the feature that intervals 106 are provided between the dark stripes 105 which are of different breadth; the mean distances y (Fig. 7) are, however, all alike, so that there are between the dark stripes 105 transparent intervals 106 the breadth of which is in accordance to the component-curves of a respective character. The cells 87 or (and) 87 a are excited in certain frequencies by said distance whereas the fluctuations of the current are produced by the width or breadth of the portions 105 and 106 of the band. The intervals of frequency 106 (Fig. 7) can be produced, of course, also by equally distributed and completely non-transparent stripes upon the bands 97a and 97B.

The invention may be used for the remote transmission of written characters either by means of conducting wires or by wireless. The wireless transmission may be eifected by means of any of known transmitting and receiving apparatus for wireless-telegraphy.

A particularly advantageous method in the transmission of the component curves by wireless consists in superimposing on a carrier wave two diflerent oscillations of a definite low periodicity, of which the intensity of one is varied according to the path of the abscissa curve and the intensity of the other is varied according to the path of the ordinate curve. At the receiving station the oscillations forming the abscissa and the or- I transmitted by an aerial 135 dinate curves which have been superimposed on the carrier wave are again separated out by means of known resonators and caused to act on a writing member in such a manner that it writes the desired written signal as the resultant of the abscissa and ordinate curves. Particularly suitable for the production of the said oscillations to be superimposed on a carrier wave is the device illustrated in Figs. 1) and 6, 7 in which the intensity depends on the width of the intervals 106 and the periodicity depends on the number of intervals struck per second by the light ray 95, 95 95.

In Figs. 8 and 9 there is illustrated diagrammatically a device by means of which two oscillations, which in intensity correspond with the course of the COI11- ponent curves, are simultaneously superimposed on a carrier wave and are again separated at the receiving station.

Fig. 8 shows a diagram for a wireless valve or tube transmitter in which two different oscillations of low frequency, for example of 500 and 700 periods, are superimposed on a carrier wave of 100000 periods. The diagram of the transmitter-consists of valve 134 of which the coupled aerial circuit 135 is energized for undamped oscillations by means of a back coupling coil 135" in the grid circuit 135 On the grid circuit 135 there are superin'iposed by means of a low frequency transformer, of which the secondary winding 135 is included in the grid circuit, the low frequency (sound frequency) oscillations. In order to impress on the grid circuit through the same secondary winding simultaneously a number of oscillations of low periodicity, the primary winding is divided into two separate windings 135 and 135 Toeach separate winding are supplied oscillations of definite frequency, for example of 500 and 700 periods, which are then supplied to thegrid 134: through the winding 135. The waves are and received by the receiving aerial 136 of the receiving station shown diagrammatically in Fig. 9. The aerial circuit is tuned to the carrier wave to be received on which the low frequency oscillations are superimposed. The valve 137, arranged as audion, connected thereto rectifies the carrier wave so that the superimposed oscillations oflow frequency are received in the anode circuit separate from the carrier wave but still intermingled. In order to separate the different frequencies from one another there are provided two resonance or sifting circuits 138, 138 which are tuned to the desired oscillations of low periodicity (500 and 700 periods). The separate oscillations effect, in accordance with their intensity the setting down of the desired letter by means of the electromagnets 67, 67, the rods 3, 3 and the pencil 4.

Finally 139 indicates a filament resistance for the valve.

The particular advantage which is ob tained by the superimposing of the oscillations corresponding with component curves on a carrier wave exists in the considerable simplification of theapparatus, in that for the simultaneous transmission of the two component curves only one transmitting and receiving device is necessary; and further in that the synchronous operation of the Writing member is effected with certainty.

I claim:

1. An electric device for transmitting written characters comprising a transmitter having cells sensitive to light, circuits in which the said cells are included, a source of light the rays of which affect the said cells, means adapted to produce fluctuations of light in conformity with component curves obtained by the decomposition of a particular character, the device including a receiver means adapted to be moved by the transmitted fluctuations of electric energy, and IOCUXDPOSO the transmitted character, and a writing member supported by the said means.

2. An electric device for transmitting written charaeters, comprising a transmitter including cells sensitive to light, circuits in which the said cells are included, a source of light, light filtering means between the source of light and the said cells which varies in conformity with component curves obtained by the decomposition of a particular character, means for moving the light filtering means, means between the source of light and the light-filtering means to transmit the light-rays so that they fall only upon that light filtering means which pertains to one certain character, the device including a receiver means adapted to be moved by the transmitted fluctuations of electric energ and to recompose the transmitted character, and a writing member supported by said means.

3. An electric device for transmitting written characters, comprising, a transmitter including cells sensitive to light, circuits in which the cells are included, a source of light, a light filter between the source of light and said cells, the perviousness of which to light varies in conformity with component curves obtained by the decomposition of a. particular character, means for moving the light filter, means to transmit the light-rays so that the rays fall only upon the light filter which pertains to one certain character said device including a receiver means to be moved by the transmitted fluctuations of electric energy and to recompose the transmitted character, and a writing member supported by said means.

4. An electric device for transmitting written characters, comprising, a transmitter,

including cells sensitive to light, circuits in which the said cells are included, a source of light, a hollow rotary body, light-filtering means supported thereby for controlling the passage of the rays of light, the perviousness to light of the light filtering means varying in conformity with component curves ob tained by the decomposition of a particular character, means for rotating the said rotary body, means between the source of light and the light-filtering means to transmit the light-rays so that the rays fall only upon that light-filtering means which pertains to the one certain character, said device including a receiver means movable by the transmitted fluctuations of electric energy to recompose the transmitted character, and a writing member supported by said means.

5. An electric device for transmitting written characters, comprising a trans mitter, including cells sensitive to light, circuits in which the cells are included a source of light, light filtering means between the source of light and the said cells the perviousness of which to light varies in conformity with component curves of a certain character, means whereby certain frequencies are produced by the rays caused to fall upon the said cells sensitive to light, means for moving the light-filtering means, means between the source of light and the light filtering means to transmit the light rays so that they fall upon that light-filtering means, only which pertains to one certain character, said device including a receiver means adapted to be moved by the transmitted fluctuations of electric energy and to recompose the transmitted character, and a writing member supported by said means.

6. An electric device for transmitting written characters, comprising, a transmitter, including cells sensitive to light, circuits in which the said cells are included, a source of light, light filtering means as control members between the source of light and the said cells, the perviousness of which to light is in conformity with component curves obtained by the decomposition of the selected char acter, means for moving the light-filtering means, a light screen between the source of light and the light-filtering means, a slot in the said screen, a strip between the said light screen and the light-filter means, perforations in the said strip which correspond to the light-filter means, whereby the rays fall upon that light-filtering means only which pertains to one certain character, means to intermittently move the perforated strip in accordance with the movement of the light filtering means; said device including a receiver means movable by the transmitted fluctuations of electric energy to recompose the transmitted character, and a writing member supported by said means.

7. A method for transmitting written characters which consistsin decomposing the curve-lines of the character into its component-curves, producing fluctuations of electric energy in accordance with the path of the component-curves, imparting fre quencies to the fluctuations of electric energy, superimposing the frequencies which in intensity correspond with the component curves of a written character on a common carrier-wave, and separating the said frequencies at a receiving station by means of resonators and causing them to act on and correspondingly influence a writing member.

In testimony. whereof I afiix my signature.

HEINZ PEIN.

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