US1737407A

US1737407A - Method of and apparatus for radioreception

Info

Publication number: US1737407A
Application number: US88782A
Authority: US
Inventors: Jr William M Bruce
Original assignee: Individual
Current assignee: Individual
Priority date: 1926-02-17
Filing date: 1926-02-17
Publication date: 1929-11-26
Anticipated expiration: 1946-11-26

Description

Nov. 26, 1929. w. M. BRUCE, JR

METHOD OF AND APPARATUS FOR RADIO RECEPTION Filed Feb. 17. 1926 2 Sheets-Sheet wuemtoz M 4 WV Nov. 26, 1929. 1 w. M. BRUCE. JR 1,737,407

METHOD OF AND APPARATUS FOR RADIO RECEPTION Filed Feb. 17, 1926 2 Sheets-Sheet 2 Q Q E in f ail D I 1 mm m m u mlioz P'atented Nov. 26, 1929 WILLIAM M, BRUCE, an, on SPRINGFIELD, orrro METHOD OF AND APPARATUS FOR B-NADIORECEPTION Application filed February 17, 1926. Serial No. 88,782.

My invention relates to methods and apparatus for radio receptions and it more particularly relates to methods and means for extending the band of radio frequencies on which broad-casting so called can be received and also to materially amplify the reception of radio broad-casting.

In the present state of the art broad-castingis limited to a band of frequencies ranging from approximately 200 to 600 meters and it has not been found practical with the present apparatus in use to receive and amplify the broad-casting on different wave lengths particularly .those shorter wave lengths or higher frequencies.

Also in the present state of the art receiving sets for broad-casting especially those of higher amplifications employ several stages of radio amplification as well as a seriesv of stages of audio amplification. F or reasons number of audio amplification as the frequencies are increased the stages of radio amplifications become more difiicult. In my improved system many of these difficulties are overcome and it is made possible to receive and amplify radio messages and programs on the higher frequencies and shorter wave lengths and also to further amplify such messages on the present band of broad-casting frequencies.

Experiments seem to have demonstrated that the shorter wave lengths or higher frequencies when modulated byvoice or otherwise are capable of being transmitted to longer distances and with less initial power or wattage than the longer wave length or lower frequencies. Wave lengths from around to meters have been employed successfully in trans-Atlantic transmissions and for a distance of approximately one half the circumference of the globe, where the longer wave lengths and lower fre uencies have not been successful; besides suc modified short wave radio frequencies can not be received on the present receiving apparatus in general use.

In carrying out my invention I make use of a local generated frequency adapted to be received on an ordinary receiving set or upon a recelving set adapted to the particular frequency determined upon to be generated at the local station and I modulate these locally produced frequencies or oscillations by the incoming signals of a different wave length or frequency. These local frequencies thus produced can be detected and amplified to the desired degree by the usual apparatus now in use and if desired can be further increased and amplified by employing another set of oscillations locally produced to another receivlng apparatus and this can be continued until the amplification reaches a volume, not possible by the present methods.

In the accompanying drawings, Fig. 1 is a diagrammatic view of an apparatus em bodylng my invention. Fig. 2 is a detailed view relating particularly to the local oscillator or the means for producing the local oscillations. Fig. 3 is a diagrammatic View showing the means for extending the range of amplification by the use of several intermediate oscillators for generating local oscillations or frequencies.

Referring to Fig. 1, the apparatus may be said to include three principal features: 1) a detecting apparatus for'any desired band of frequencies, preferable of lower wave lengths than are now used in the usual broad-casting, say from '25 to 100 meters; (2) an oscillator or device for producing radio frequency oscillations having a frequency difierent from the incoming signals, and if it is to be used with the usual broad-casting receiving sets it would have a frequency within a band of say from 200 to 600 meters which the receiving apparatus is best adapted for; for instance, it could have an oscillation which would produce frequencies of say 800 meters. (3) This represents the other section of the apparatus which may be an ordinary receiving set with the usual detector and amplifiers. In this Fig. 1

0 represents an aerial and b a thermionic tube mary p of an audio frequency transformer t where they are impressed upon the locally generated radio frequency produced by the oscillator 2. As these oscillator circuits are well known it is perhaps unnecessary to'describe them in detail.

The locally produced oscillations modified by the incoming signals relayed by the detector b of the detecting apparatus 1 are then transmitted to the receiving apparatus 3 which I have illustrated as of the two tube regenerative type, tube 6 being a detector and the tube b an amplifying tube with adjustable inductance, such as the ordinary variometers 'v and 1 I have shown in the section 3 of this View a connection to the aerial a which may be employed if desired and there is provided in connection with the aerial a, a double-throw switch 8 so that in one position the aerial would be connected to section 1 of the receiving apparatus and when in the other position it would be connected to section 3. By this arrangement when the switch is in the position shown in full lines, the radio reception would be through section 1' for short wave lengths and detector b and the usual circuits for this apparatus and the incoming signal would, through the audio transformer 25, modify the locally generated high frequencies oscillations'which would in turn be picked up by the detector 6 of section 3 of the apparatus and there be amplified and received on the usual receiver 1'.

In the event it was desired to receive messages impressed on longer wave lengths or lower frequencies, for instance those in the present broad-casting band, by throwing the switch to the position shown in dotted lines the detector 1 and the oscillator 2 would be cutout and messages on the longer wave lengths be received directly on the receiving section 3 in a normal manner.

In Fig. 3 I have shown a method of increasing the amplification by the use of a plurality of oscillators producing or generating local radio frequencies or oscillations and in this Figure 3, 1 represents the detector apparatus, 2 the first oscillator modulated thereby, 3 a receiving set, 4 a second oscillator, and 5 a second receiving set. In this figure there are shown in the preliminary detecting circuits a detector and two stages of audio frequency amplifications. The oscillator 2 is the same as that shown in Fig. 1 and the receiving set is shown with three stages of radio frequency amplification and two stages of audio frequency amplification; at 4 is shown a second oscillator the same as at 2 and the received messages on the receiving set 3 are transmitted to the oscillator 4: and modulates the frequencies produced by the second oscillator' l which are in turn transmitted to and received by the second receiving apparatus 5. In this way itis possible to use a very large number the usual receiving sets.

'6 and b are amplifying tubes connected by radio frequency transformers to the detector circuit and transmitted from the plate of the second amplifying-tube b to the oscillator tube 6 Any well known circuit may be employed with the usual inductance and capacity to produce oscillations which will be modulated by the incoming signals from the plate circuit of'the tube 6 through the audio frequency transformer t and will in turn be picked up by the detector tube 1)? of the receiving set 3 where they may be amplified by the radio frequency transformer and tubes b? and b and thence further amplified by the tubesb and Z)". From the plate circuit of the tube 5 the audio frequencies would be impressed upon and modulate an additional set of oscillations produced bythe oscillator 4,

which in turn, would be picked up by the detector tubes of the receiving set 5 and ampliradio frequency and audio frequency amplification and finally received by the receiver 1.

I have demonstrated in actual use that by a detector set of two tubes i. e., a detector fied in the usual way by various stages of and one stage of audio frequency amplification, signals or messages can be picked up on high frequencies, say 25 to 60 meters in length, and can be successfully used to modulate oscillations locally produced of say 300 meters and can be impressed upon an ordinary two or three tube regenerative circuit with much less interference and much greater volume than when an ordinary receiving set of five or six tubes is employed. It has been this character broad-casting on high frequencies of the order of 41 and 61 meters can be received on a three tube regenerative set through a detector and local oscillator producing frequencies of the order of 300 meters with greater definition and volume and less interference than can be obtained on the present broad-casting band with the usual receiving sets having a detector and several stages of radio and audio frequency amplification.

By the use of this invention it Will be seen that receiving sets-now in use that are limited to a band of oscillations from say 200 to 600 meters can be employed with a band of much higher frequencies, by the addition of the detector set for, high frequencies arranged to modulate locally produced oscillatlons having a frequency within the band of demonstrated that-by the use of a device of It is also possible by this system to use a plurality of receiving sets at any desired frequency with a larger range of amplifications and with a minimum amount of disturbance than is possible with the present method of reception.

It is possible to amplify various wireless signals either telephonic or telegraphic or of continuous wave or damped wave transmission when radio frequencies are transmitted to the local oscillator as in the case of telegraph signals a radio frequency transformer would be substituted for the audio frequency transformer between the first receiver and the oscillator.

Having thus described my invention, I claim:

1. A receiving apparatus for wireless signals comprising an aerial, a detector for high frequency oscillations, an oscillator, and means for connecting said detector to said oscillator so that the modulated high frequency oscillations from the detector will modulate the oscillations of said oscillator, a receiving device embodying a detector and amplifier to detect and amplify the modulations of the local oscillations, and means whereby the aerial may be connected to one of these detectors and disconnected from the other detector.

2. A receiving apparatus for wireless reception embodying a plurality of detecting and amplifying devices and an oscillator between said devices and connected thereto so that the audio modulations of the first de-" tector will modulate the'oscillations of said oscillator and said modified oscillations be detected and amplified for reception by the second detecting and amplifying device, and aerial connections, with means for connecting and disconnecting either of said detecting devices with the aerial.

3. In a receiving apparatus for wireless reception, a plurality of receiving devices and an oscillator, means for coupling said oscillator to two of said receiving devices so that the detected signal modulations in the output circuit of one receiver will modulate the locally produced oscillations of said oscillator and the other receiver will detect and amplify the locally produced oscillations, an aerial connected to the input circuit of each receiving device and switch means in the input of the second receiving device adapted to disconnect said input from its aerial and connect it to the output of said oscillator.

4. The combination with a radio receiving set arranged to detect and amplify signals formed as modulations upon a relatively low frequency carrier wave, of an attachment therefor comprising a detector to detect signals formed as modulations upon a relatively high frequency carrier wave, said frequency being too high for adequate reception by said radio receiving set, and an oscillator to produce oscillations of a frequency within the receptive capacity of said radio receiving set, and means for impressing the modulations detected by the detector, upon the oscillations produced by the oscillator, and means for feeding said modulated oscillations to said radio receiving set.

5. The combination with a radio receiving set arranged to detect and amplify signals formed as modulations upon a relatively low frequency carrier wave, of an attachment therefor comprising a detector to detect signals formed as modulations upon a relatively high frequency carrier wave, said frequency being too high for adequate reception by said radio receiving set, said attachment also comprising means for producing oscillations at a frequency within the range of said radio receiving set, means for impressing the detected modulations upon said oscillations, and means for feeding the said'modulated oscillations to said radio receiving set. a

In testimony whereof, I have hereunto set my hand this 11th day of February, 1926.

WILLIAM' M. BRUCE, JR.