US1648689A

US1648689A - Condenser transmitter

Info

Publication number: US1648689A
Application number: US101203A
Authority: US
Inventors: Hund August
Original assignee: Wired Radio Inc
Current assignee: Wired Radio Inc
Priority date: 1926-04-10
Filing date: 1926-04-10
Publication date: 1927-11-08
Anticipated expiration: 1944-11-08

Description

Nov. 8, 1927. v

A'HUND 1,648,689

CONDENSER TRANSMITTER Filed April 10. 1926 I law-1' 000 00 0000000 0000000000000 w 00000000000 0000 1 0000000000 000000 00000 000000000000 ooooooooooooooooooo o oooooooooooooooo ooo 000000000000000000000 ooooooooooooooooooooooa Z 00o 0000000o0000 0000000 00 o00o0o00o00o0000000 00000000000 00000 000000 OOOOOOOOOOOOOOOOOOOOO 000000000000 000000000 1 0000000 0 0000000 0 1 000000000 0000000000 000000 0 000000000 1 000000000000000 ATTORNEY e Patented Nov. '8, 1927-.

UNITED STATES AUeus'r noun, or nn'rnnsna, MARYLAND, Assienon 'ro NEW YORK,

WIRED namo, Inc, or.

N. Y., A conrona'rron'or DELAWARE.

CONDENSER rnnns arrrnn. I I

I Application llled April 10,

My. invention .relates broadly to voice modulating apparatus and more particularly to a condenser type sound detector and transmitter. I

One of the objects of my invention isto provide an extremely sensitive sound trol circuit of an electron tube ampliher for modulating electrical with sound vibrations.

Another object of my invention is' to pro-- vide a construction of condenser transmitter in which sound-at relatively great distances may be detected and utilized to control the circuit of a condenser transmitter for modulating electrical currents with substantially no dlstortion.

Another object of my invention is to provide a simplified construction of electrostatic transmitter in whicha sound distribution plate is, provided for uniformly distrib uting sound vibrations over the area of a relatively flexible plate which .may be chan ed in position by the impinging of soun .waves thereagainst, the operation of an electron tube system. Another object of my invention is to provide aninexpensiv'e construction of condenser transmitter which may be readily manufactured from a relatively small number of parts and yet will have the property of great sensitivity and ability to 'efiectively control theoperation of an electron tube system for the production of modulated current, in ac- 3:, cordance with sound vibrations.

My invention will more clearly understood from the specification hereinafter following b reference to the accompanying drawings w erein: Figure 1 is a front elevation of the condenser transmitter embodying the principles of my invention; Fig. 2 is a cross-sectional view taken through the condenser transmitter on line ,2-2 thereof; and Fig. 3 shows the electrical connections of the condenser transmitter of my invention with anv electron tube system. c

.Heretnfore 1n the art condenser trans- .mitters have been relatively insensitive as compared with the usual carbon microphone transmitter. Prior constructions of condenser transmitters have been relatively complicated-and expensive to manufacture. My condenser transmitter construction 'is'relatively simple and requires only a small detecv tor and transmitter for operation in'the concurrents in accordance I condenser transmitter.

plates and ring members being secured for controlling 1926. Serial No. 101,203.

number of parts and yet'y the device is highly sensitive to sound vibrations and has been used for the dete( ;tio1rof.- very sounds andthe modulation vof electrical currents in accordance with the sound vibrations.

Referring to the drawings in more detail reference character 1 designates one of the end plates constituting one electrode of the Reference character 2 designates an opposite end. plate of the condenser transmitter which is spaced-from the plate l by means of concentmcally posi tioned insulated ring members 3 and 5, the

together by means of bolt members 6 which pass through the several members, the bolts being secure which bear upon bers '7, located in the plate member, 1. In this manner the plate member 1 is substantially insulated from the plate member 2. flexible sheet of 'metal 8 is stretched over the annular flange or bead 4 of the ring member 3- and has its outer periphery 9 PP ed between the insulated ring members 3 and 5 stretching the sheetB in the manner of a drum. ;The plate 8 is formed of very thin metal foil which is readily moved by sound vibrations impinging thereagainst. The plate 8 forms the other electrode of the condenser detector. The ring member 5 telescopes over the ring member 3"in securing the foil 8 over the head portion 4. The ring members 3 and 5 fit snugly together in the manner of hoops for clamping the flexible foil 8 therebetween. The plate member 1 is provided witha plurality of apertures represented at 10 positioned throughout the area of plate member 1 which is bounded feeble d therein by means of nuts.

the insulated bushing mem- 1 by the dotted line 11- forming a space or 7 gap 12 immediately over the flexible foil sheet 8.

In Fig. 3 I have shown the electrical connections of the condenser transmitter in an electron tube circuit. The electron tube circuit comprises tubes 1 1, 15 and 16 in the form of a resistance capacity coupled amplifier'whose input circuit is controlled by the condenser transmitter as illustrated. Plate 1 of the condenser transmitter (01' detector sensitivity) connects with the grid electrode of the input. circuit, while plate 8 connects with the filament electrode of tube 14;. A high potential direct current is unelectrodes.

pressed across the electrodes of the condenser transmitter. This potential may be derived from the B-battery source or it may be obtained from an independent source.

In the operation of the condenser transmitter the sound enters through'the many circular apertures 10 provided in the metallic plate 1. In a preferred embodiment of my invention these apertures have a diam eter of about-{ of an inch and their centers are spaced of an inch, that is, their centers are the corners of small squares whose sides is of an inch long. This leaves enough active material in plate 1 for the condenser action and admits the sound very uniformly. In one of my designs I employan outside diameter of 5" and an efl'ective inside diameter of 4".

For the best results I apply about 200 volts across the condenser electrodes for establishing the normal charges on the condenser The sound vibrations which impinge upon the flexible foil sheet 8 by passmg through the apertures the flexible sheet 8, for varying the syfagcial relation between plate 1 and flexible sheet 8 for varying'the electrostatic capacitytherebetween.

The condenser transmitter of my invention has proven so sensitive that I have successfully detected the speech of a person talking in an ordinary tone of voice 150 feet distant from the vtransmitter. I have detected the disturbances offered by approaching aircraft at a distance of several miles, and other important a plications of the invention have been marl the initial sound disturbance is relatively slight, so slight in fact that the ear would normally not perceive such sounds, and yet Where positive detection of these slight sounds has been accomplished. Mention may be made herein of the ready adaptability of the invention in the faithful recording of music and voice records, detectophone pick-up and devices for assisting the deaf to hear. Many other applications of the invention will readily suggest themselves to those skilled in the art. 7

While I have described my invention in a certain preferred embodiment, I desire it to be understood that modifications may be 10 bodily move e in instances where b made and that no limitations upon the invention are intended other than are imposed by the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is as follows:

1. A condenser transmitter comprising in combination a pair of insulated ring members, one of said ring members having an annular flange and the other of said ring members fitting around said annular flange in the nature of a hoop, a flexible sheet of metal stretched over said annular flange and gripped between, said ring members,and an apertured --.conductive plate supported by said ring members in spaced relationship to said flexible plate memberfor permitting the free passage of sound vibrations to said flexible plate member for, varying the electrostaticcapacity between said conductive plate member and said flexible plate member.

2. A condenser transmitter comprising in combination a tioned insulated hoop members fitting one over the other, a sheet of flexible metal stretched over said hoop members forming a drum-like surface, and an apert-ured metallic plate member secured to saidhoop members in spaced relation to said sheet of flexible metal whereby sound vibrations may be directed against said sheet of flexible metal or varying the spacial relation between said apertured plate member and said flexible sheet member.

3. A condenser transmitter comprising in combination a pair of metallic plate memers, a pair of insulated rim members telescoped one over the other, and a flexible metallic sheet stretched between said rim members and directly parallel with one of said said metallic plate permitting the impingement of sound vibrations against said flexible sheet member for member and said flexpair of concentrically posi-