US2380666A

US2380666A - Telegraph signal transmission system

Info

Publication number: US2380666A
Application number: US496903A
Authority: US
Inventors: Morrison Montford
Original assignee: Individual
Current assignee: Individual
Priority date: 1943-07-31
Filing date: 1943-07-31
Publication date: 1945-07-31
Anticipated expiration: 1962-07-31

Description

July 31, 1945. M. MORRISON TELEGRAPH SIGNAL TRANSMISSION SYSTEM Filed July 31 1943 I 7/ (1} ct S //////II////// I! m u lllll /ll N III/HUN! HHHHHIH P Fig 3 3 Sheets-Sheet l Wzww July 31, 1945. M. MORRISON TELEGRAPH SIGNAL TRANSMISSION SYSTEM Filed July 31, 1943 3 Sheets-Sheet 2 INVENTUR. Mo/vimfip MOAW/SGN M. MQRRISON TELEGRAPH SIGNAL TRANSMISSION SYSTEM Filed July 51, 1943 3 Sheets-Sheet 3 Q QQQOOO mm MN INVENTOR. MONT/0R0 MORRISON W g July 31, 1945.

Pa tented July .31, 1945 TELEGRAPH SIGNAL TRANSMISSION SYSTEM Montford Morrison, Upper Montclair, N. 1. Application July 31, 1943, Serial No. 498,908

Claims.

This invention relates to systems of telegraphic transmission in which optical pick-up of the signals is used, and relates in particular to such systems employing carrier currents.

Among the objects of the invention are: to provide a simple and emcient means for generating I a large number oi accurately-fixed carrier frequencies; to provide a simple and effective means for modulating the light, used in the optical pickup system, into sinusoidally varying beams before the beams are employed in the pick-up operation; to provide means for the simultaneous application of a plurality of scanning beams to a single signal copy to be transmitted; to provide means for use of both the transmitted and the reflected light from the si nal copy, in the optical pick-up system; to provide means for the transmission of Baudot and other similar codes to receiving stations not equipped with synchronized apparatus; to provide means for the transmission of Baudot and other codes under conditions which greatly reduce the errors of reception, due to interference; to provide a method of telegraph transmission directly from a plain letter text without requiring synchronism at the receiving station; and to provide a modification for letters, hunter ais and other signal characters used in telegraph transmission, which reduces the band -wicith of the transmission frequencies required and re duces the interchannel interference in the re ceiving circuit-filters.

Further and other objects will be obvious from the specification when read in connection with the accompanying drawings. and the scope of the invention is set forth in the claims hereto.

In the drawings:

Fig. l is a partial section of one embodiment of the invention used as a transmitter; Fig. 2 is an enlargement of a section (f Fig. 1, taken at the plane marked AB in thit figure and looking west, Figs. 3, 4, and 5 are enlargements of different modifications of the circular tracks shown in Fig. 2; Fig. 6 is a section oi Fig. 1 taken at the plane C-D or that figure and looking east. and with a tape-puller added for clearness: Fig. 7 is an enlargement of a fragmentary view of Fig. 6 taken at the plane EF and looking ast. and which shows the channel form of guide for thetransmlssion tape; Fig. 8 is a rear view of that part of the tape channel shown in Fig. 6, between the dotted lines G-H and I-J; Fig. 9 is an enlargement of the tape shown in Fig. 6; and Fig. 10 is a form of transmission tape used for Baudot and other similar codes.

In Fig. l, l is a constant speed motor which may be of any form whatever, and its function is to revolve the shaft 2 at a highly constant speed. This may be a small synchronous motor directly applied to a constant frequency alternating current system; it may be a synchronous motor driven alternating current derived by ampliflcation from a tuning fork oscillator; or, preferably, it may be of the highly constant speed form driven directly from a direct current source, as described in my co-pending patent application filed July 28, 1943, Serial Number 496,389.

Onto shaft 2 is mounted a plate 3, which may be constructed in a, variety of forms. The construction of plate 3 will be better understood from Fig. 2 which is a fragmentary enlargement there of. Plate 3 may be constructed of a photographic film or, preferably, a photographic plate, in which latter case, there is a freedom from Plate 3 is provided with a series t shrinkage. light tracks, indicated by l, 5, t, "i, i 9 and These light tracks, in the case of a pilot-camp film, which results in either form, si'iown. in. Fig. 4, or a shown in These light tracks in reaiity or; traclrs for the generation oi frequencies, in the same that the so tracks on motion. picture film serve for the eration of sound irequencies,

The light traciis produced on plate 3 are formed N into continuous circular paths.

These light tracks, or carrier-current frequency tracks, revolve continuously behind a slit ii, Figs. 1 and 2, which slit is sufficiently narrow to pro vide substantially sinusoidal variation in the total light flux that is permitted to be transmitted by means of the combined action of the revolving carrier frequency track and the stationary slit, as will be appreciated by those skilled in the art to which this invention appertains. In some cases. instead of a photographic plate, I may use a thin metal opaque plate provided with perforations, such as shown in Fig. 3, and which provides the same character oi light flux modulation, but the pattern of the perforation is modified so as to permit more metal to be retained between perforations, thereby retaining considerable strength in the metal plate.

Returning to Fig. 1, i2 is a so-called exciter lamp. of a conventional variety, such as used in standard 35 mm. motion picture optical sound systems; It represents a conventional set of condenaing lenses which focuses the light onto the revolving carrier frequency light tracks, in a manner somewhat similar to the way in which the light is focused on sound track in a motion picture film; the difference being that in a motion picture film, the image of the slit employed is focused on the sound track, whereas in the present case the light is first focused on the carrier frequency light track, then passes through the slit in a multiplicity of beams varying in periodicity in light flux modulation representing the periods of the different frequencies of carriercurrent used. This multiplicity of modulated light beams is illustrated by the lines diverging from slit H, which pass through a projection lens system I. which accurately focuses each beam onto a desired part of the tape II. which is shown in its edgewise position in the figure.

An enlarged section of tape II is shown in Fig. 9, which comprises a translucent paper support It, onto which specially-designed character H, II and II are printed. These characters are preferably printed on both sides of the translucent support I. This double printing increases the opacity of the characters and thereby improves the quality of the optical pick-up.

The rectangles Iii to 2| represent the images of the combined slit and carrier frequency tracks. as projected upon the tape II, Fig. 1.

These images It to 18.. inclusive. vary in in :H

tensity sinusoidally with the peri ii of the carrier frequency of a te which these trequenciiaal circuit, as will. be her scribed. That is. s intensity m such a it Fig. *l is a fragments the dotted line the channel. M,

tape is pulled, and in. Pig. 6. a tape puller is indicated for clearness.

The characters ABCDEF, etc., are accurately located on tape II with reference to the lower side II of the tape II. The channel 34. Fig. 6, is provided with a gentle spring. actuated member ll. Figs. 6 and 8.

Referring to Fig. 8, this is a fragmentary view of the part of the channel N which lies between the dotted line G-H and 1-4, and the member II. Figs. 8 and 8. is a loose channelled part held by a fine spring ll, which is fixed to pins 80 and I! on a channel part 34 and to a loose member 88 by pin ll. ll is an opening in the channel II to permit the transmission of light at this loca tion.

The function of this member II is to keep the tape ll pressed against the lower side of the channel ll, keeping the characters accurately located with reference to the modulated light beams.

Referring to Fig. 9, I prefer to modify the configurations of the letters and characters in such a way as to reduce the rate-of-change in the light modulation produced by the character. As the character moves into the light image, instead of striking a parallel line, I prefer to use a graduated area such as shown in ii which reduces the rumor-change, as will be understood by those mathematically equipped in the art of optical light pickups.

l i til we embodiment hi my invention a d in the place employing optical pick-up from substantially opaque characters on a translucent paper suprt, comprising an optical system directing a light-beam upon the support and upon said characters to be transmitted, a photocell in the path of said light-beam and receiving light after said light has been transmitted through said vsupport, and a concave reflecting surface gathering a substantial portion of the light reflected from said support and directing said light upon the cathode of the same photocell.

2. A telegraph signal system employing optical pick-up from substantially opaque characters on a translucent support comprising means for moving and guiding said translucent support; a source of light on one side of the path of movement of said translucent support; a photo-sensitive member on the opposite side of said translucent support; an optical system for directing light from said light source through 'said translucent support upon said photo-sensitive mem ber; and additional means for gathering reflected light from the surface of said translucent support and reflecting said light upon said photosensitive member.

3. A telegraph signal system employing optical pick-up from substantially opaque characters on a translucent support comprising means for moving and guiding said translucent support; a source of light on one side of the path of movement of said translucent support; a. photo-sensitive member on the opposite side of said translucent support; an optical system for directing light from said light source through said translucent support upon said photo-sensitive member; and a concave reflecting surface for gathering reflected light from the surface of said translucent support and reflecting said light upon said photo-sensitive member.

4, A telegraph signal system employing optical pick-up from substantially opaque characters on a translucent support comprising means for moving and guiding said translucent support; a source of light on one side of the path of movement of said translucent support; a photo-sensitive member on the opposite side of said translucent support; an optical system for directing light from said light source through said translucent support upon said photo-sensitive member; and a concave reflecting surface for gathering reflected light from the surface of said translucent support and reflecting said light upon said photo-sensitive member; said concave reflecting surface being disposed in the path of light from said light source to said photosensitive member; an opening in said concave reflecting surface to permit passage of light from said light source to said photo-sensitive member.

5. A telegraph signal system employing optical pick-up from substantially opaque characters on a translucent support comprising means for moving and guiding said translucent support; a source of light on one side of the path of movement of said translucent support; a photo-sensitive member on the opposite side of said translucent support; an optical system for directing light from said light source through said translucent support upon said photo-sensitive member; and a concave reflecting surface for gathering reflected light from the surface of said translucent support and reflecting said light upon said photo-sensitive member; the focus of said concave reflecting surface being located between said translucent support and said photosensitive member.

MONTFORD MORRISON.