Патент USA US2109452код для вставки
March 1, 1938. ‘G. L. D‘IMMICK ‘ 2,109,452 RECORDING OF SOUND Filed Nqv. 2, 1935 r792 \ 23 U . . C] ' ' [:1 [:3 /2/ [I] II] D, . C1 E] ' ~ INVENTOR GAVE/WV L. .aMM/cz BY' ATTORNEY Patented Mar. 1, 1938 2,109,452“ UNITED STATES PATENT OFFICE 2,109,452 RECORDING OF SOUND‘v Glenn L. Dimmick, Audubon, N. J., assignor to 1 Radio Corporation of America, a corporation. of Delaware , Application November ‘2, 1935', Serial No. 47,968 9 Claims. r (01. 179¢+100.3) “ This invention relates to the recording of sound ture l2 of a mask l3 and a lens M to the galvanom- eter recorder mirror l5 which ‘is vibrated i111 ac~ cordance with the signals to be recorded. Light or the like, and has for its principal object the provision of an improved apparatus and method of operation for obviating certain kinds of distor tion which tend to occur in the reproduction of sound from a multiple track or push-pull record such as that disclosed by my copending applica tion Serial No. 674,805, ?led June 8, 1933 and as signed to the same assignee as the present ap plication. As pointed out in the aforesaid copending ap plication, the distortion caused by fogging of the record valleys and under-exposure of the record peaks is avoided by the provision of two similar sound tracks displaced in phase by 189 degrees and is re?ected from the mirror [5 through a lens Hi, the light slit I‘! of a screen [8 and lenses l9 and 29 to the light sensitive surface of a record strip 25 which is supported upon and moved over the surface of a roller 22. The image of the aperture l2 re?ected by the mirror i 5 onthe member I 8 is indicated at 23. As will be readily understood, this image is‘ in the 10 form of a parallelogram offset at its opposite ends, is vibrated transversely of the slit and produces two sound tracks 24 and 25 (Fig. 3) which are dis arranged to be simultaneously reproduced and combined for operating a loudspeaker or the like. While the types of recorder disclosed by the afore said application obviate the distortion mentioned above, their operation sometimes involves the di?iculty that the separate sound tracks tend to overlap at high modulation and are not readily reproduced without distortion when such over lapping occurs. In accordance with the present IO Ll invention, such distortion of the reproduced sound 1 is minimized or avoided by the provision of means for producing a light beam of such con?gura tion that the two sound tracks are maintained in spaced relationship with one another irrespec tive of the extent to which they are modulated. As hereinafter indicated, one suitable means of determining the contour or shape of the light beam is a mask having an aperture provided with a central portion having its edges sloped with re spect to a cooperatively associated light slit and with end portions having their opposed or inner ‘edges perpendicular to the light slit and spaced apart to maintain a predetermined spacing be tween the two record tracks. For convenience of This form of aperture has the advantage that overshooting of the light beam due to excessive modulation can not cause one ‘of the, modulation is avoided. I claim: ,_ 1. A signal recorder including means de?ning a light slit, means for producing a light beam having the form of a parallelogram offset to space its ends from one another along the length ‘ ' slit, and signal responsive means operable to vibrate said beam across said slit transversely to said dimension. 35 expression, this aperture is sometimes hereinafter designated as having the form of a parallelogram oil‘set at its opposite ends. The invention will be better understood from the following description when considered in con nection with the accompanying drawing, and its scope will be pointed out in the appended claims. Referring to the drawing, record, and means for moving said record trans versely of the light transmitted through said slit. 3. A sound recorder of the galvanometer type including means de?ning a light slit, means for producing a light beam provided with a central 45 Fig. l is a diagrammatic showing of a recorder ' constructed in accordance with the invention, Fig. 2 illustrates the form of the light beam and its relation to the light slit, and Fig. 3 illustrates the type of record produced by the recorder. across said slit. - 4. In an apparatus for producing sound tracks 50 displaced in phase The recorder includes a light source I 0 from which light passes through a lens II, the aper 55 2,109,452 2 portion, means de?ning a light slit, and signal responsive means operable to vibrate said beam across said slit. 5. In an apparatus for producing'sound tracks 180 degrees out of phase with one another, the combination of means de?ning a light slit, means for producing a, light beam having its end por 10 tions spaced apart longitudinally of said slit and angularly disposed with respect to its central portion, and signal responsive means operable to vibrate said beam across said slit in a direction parallel to the side edges of said end portions. 6. In a signal recorder including means de?n ing a light slit and signal responsive means oper able to vibrate a light beam transversely across 15 said slit, means for producing a light beam having the form of a parallelogram offset to space its ends from one another along the length di mension of said slit. '7. In a signal recorder including means de?n 20 ing a light slit, signal responsive means operable to vibrate a beam of. light transversely across said slit, a light sensitive record, and means for moving said record transversely of the light transmitted through said slit, means for direct-' ing a beam of light having the form of a paral lelogram o?set to space its ends from one another along the length dimension of said slit to said signal responsive means. 8. In a sound recorder of the galvanometer type including means de?ning a light slit and means for vibrating a beam of light across said slit, means for producing a light beam provided 10 with a central portion angularly disposed with respect to said slit and with end portions per pendicular to and spaced apart along said slit. 9. In an apparatus for producing sound tracks displaced in phase with respect to one another 15 and including means de?ning a light slit and signal responsive means operable to vibrate a beam of light across said slit, means for pro ducing a light beam having its end portions spaced apart and angularly disposed with respect 20 to its central portion. GLENN L. DIMMICK.