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Publication numberUS2458124 A
Publication typeGrant
Publication dateJan 4, 1949
Filing dateNov 14, 1944
Priority dateNov 14, 1944
Publication numberUS 2458124 A, US 2458124A, US-A-2458124, US2458124 A, US2458124A
InventorsRaymond M Wilmotte
Original AssigneeRaymond M Wilmotte
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Synchronous frequency broadcasting
US 2458124 A
Abstract  available in
Images(2)
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Claims  available in
Description  (OCR text may contain errors)

Jan. 4, 1949.

Filed Nov. 14, 1944 R. M; WILMOTTE SYNCHRONOUS FREQUENCY BROADCASTING- 2 Shee'ts-Shet 1 P ayi a 4 f f I I I SIGNAL POWER SOURCE AMPLIFER .2 7 e- I I I 5.0. FREQ. MODULAT- UHF.

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Patented Jan. 4, 1949 SYNCHRONOUS FREQUENCY BROADCASTING Raymond M. Wilmette, Washington, D. 0. Application November 14, 1944, Serial No. 563,391

11 Claims.

This invention relates to synchronous frequency broadcasting and the operation of booster or satellite stations in conjunction with a primary broadcast station.

In operating a booster or satellite station, it is important to avoid variable relative phase shifts between the video or audio signals and between the carrier waves transmitted by the primary station and the booster stations, otherwise interference will result in zones served by more than one of these stations.

It is an, object of this invention to provide a broadcasting system which will not give rise to interference and will insure synchronized broadcasting at the primary and booster stations.

The invention will be more fully understood from the following description and the attached drawing in which:

Figure 1 is a schematic diagram of primary broadcast station.

Figure 2 is a schematic diagram of a booster station.

Figure 3 is a schematic diagram of multiple program primary station,

Figure 4 shows a combined booster and relay station, and

Figure 5 illustrates the relative arrangement of a primary broadcasting station and a plurality of satellite stations, as well as the relations of the radiation patterns produced thereby.

Figure 1 shows a modulator 3 which modulates radio frequency oscillations derived from the broadcast frequency source 2 with signals from a source I. The output of the modulator may be amplified in the power amplifier 4 and broadcast by an antenna 5. A source of ultra high frequency oscillations 6 and the modulator 3 are connected to a modulator I. The ultra high frequency oscillations may be of the order of 1000 megacycles or any other suitable frequency oscillations. The modulated ultra high frequency oscillations at the output of the modulator 1 may be amplified in amplifier 8 and transmitted by an antenna 9. The antenna 9 may be a highly directive radiator, as indicated in the drawing.

The energy from the antenna 3 is picked up by an antenna l and demodulated by a detector |2 after passing through amplifier H. The amplifier H is optional and may be omitted if extremely high frequencies are used. The output of detector I2 is a replica of the modulated radio frequency waves broadcast by the antenna of the primary station. The radio frequency oscillations from detector |2 are amplified in amplifier l3 and broadcast by antenna M. In this 2 manner the same modulated radio frequency waves are broadcast in both the primary and the booster stations.

Figure 3 shows a primary station similar to 5 Figure 1 except that a plurality of radio frequency oscillators 22, 3|, each feed a modulator 23 or 33 connected to signal sources 2| and 32. In practice, one signal source may be a television source and the other may be an audio siglO nal source. The oscillator 22 may generate oscillations of a frequency between 500 and 1500 kilocycles and oscillator 3| may generate a frequency of the order of 50 megacycles for television or FM broadcasting. The outputs of the modulators 23 and 33 are fed to broadcasting antennas 25 and 35 through power amplifiers 24 and 34. The outputs of these modulators are also fed to a modulator 21 to modulate ultra high frequency oscillations derived from the oscillator 26. The output of modulator 21 is radiated by a directive antenna 28.

At the booster station, shown in Figure 4, the ultra high frequency waves are picked up by an antenna 4| and demodulated by a detector 42. An amplifier, not shown, may be connected ahead of the detector, if desired. A filter 43 selects one of the modulated carrier waves appearing at the output of the detector 42 and this carrier wave is amplified in amplifier 44 and radiated by antenna 45. A second filter 46 selects one or more of the modulated carrier waves at the output of the detector 42. A modulator 48 is connected to the filter 46 and to ultra high frequency oscillator 41 for modulating the ultra high frequency with the modulated carrier waves passed by the filter 46. The frequency of the oscillations of oscillator 41 is preferably difierent from the frequency of the waves received by antenna 4|. The output of the modulator 48 is radiated by the antenna 49. The energy radiated by antenna 43 may be picked up by another station similar to the one shown in Figure 4 or by a booster station such as shown in Figure 2. A plurality of booster stations of either the type shown in Figure 2 or Figure 4 can be operated in conjunction with the primary stations of Figure 1 or 3. Instead of demodulating the incoming signal and supplying another carrier from oscillator 41, the waves received by antenna 4| 50 may be amplified and directly fed to antenna 49. Other modifications within the scope of this invention as defined by the following claims will be apparent to those skilled in this art.

Reference is now made of Figure 5 of the drawings wherein is illustrated a single broadcasting station operating in conjunction with a pair of booster or satellite stations. Reference numeral 50 denotes a primary station of the type illustrated in detail in Figure 3 of the drawings, and which has been described in detail in the preceding portions of the specification, and includes one or more substantially omni-directionally transmitting antennae 25, 35 for transmitting primary broadcasts into an area generally denoted by the reference numeral The primary station 50 further provides means for transmitting an ultra high frequency carrier via an antenna 28, this ultra high frequency carrier being modulated with the signals transmitted by the antennae 25 and 35, and the antenna 28 being in general directional, and transmitting signals to the booster stations 52 and 53, each of which includes a directional receiving antenna 4| for receiving the ultra high frequency transmissions.

Booster stations 52 and 53 may be of the character illustrated in Figure 4 of the drawings, the latter figure including as a special case a system of the character illustrated in Figure 2 of the drawings. Accordingly, the booster stations 52 and 53 are provided with the program transmitted by the primary station 50, modulated, however, on an ultra high frequency carrier. Booster stations 52 and 53 are provided with detecting means for abstracting from the ultra high frequency carrier the modulated low frequency or broadcasting carrier impressed thereon, and for re-transmitting the latter omni-directionally via antennae 45 at each of the booster stations.

In the normal operation of a satellite system or synchronous frequen y broadcasting system of the character herein involved, the booster stations 52 and 53 are in relatively close proximity to the primary station 50, and are arranged to provide radiation patterns 54 and 55, respectively, which overlap the radiation pattern 51 provided by the primary station 50 and which, furthermore, mutually overlap to assist in obtaining broadcast coverage over an area.

Accordingly, the primary station 50, when taken in conjunction with the booster stations 54 and 55, is capable of serving a much greater area than is the primary station 50 by itself, and in the case of relatively high frequency signals such as those utilized in transm'tting television programs, the efiects of intervening geographic obstacles and the like may be overcome,

It will be realized that while I have illustrated in Figure 5 of the drawings a system utilizing two booster stations, that in practice any number of such stations may be utilized within the scope of the invention, and in accordance with the necessities of given situations. For example, where extremely hilly country must be covered in broadcasting television programs, or where a very extended area must be covered it may be desirable to provide a greater number of booster stations than two.

While I have described various embodiments and arrangements in accordance with my invention, it will be realized that modifications thereof may be resorted to without departing from the true spirit and scope of the invention.

I claim:

1. A synchronous frequency broadcasting system including a primary radio broadcasting station having a source of signals, a source of radio frequency oscillations, a modulator for modulating said radio frequency oscillations in response to said signals to provide modulated radio frequency energy, means for radiating said modulated radio frequency energy, a source of further radio frequency oscillations, means responsive to said modulated radio frequency energy for modulating said further radio frequency oscillations with said modulated radio frequency energy to provide doubly modulated radio frequency oscillations, and means for radiating said doubly modulated radio frequency oscillations.

2. A synchronous frequency broadcasting system including a primary broadcasting station having a signal source, a source of radio frequency oscillations, a modulator connected to said sources, an antenna connected to said modulator for radiating modulated radio frequency oscillations derived from said modulator, a source of oscillations of a much higher frequency than said radio frequency oscillations, means for modulating said higher frequency oscillations with said modulated radio frequency oscillations and means for transmitting said higher frequency oscillations.

3. A system in accordance with claim 2 wherein is further provided a satellite station having means for receiving said higher frequency oscillations, means for demodulating said higher frequency oscillations to obtain said modulated radio frequency oscillations, and means for radiating said modulated radio frequency oscillations.

4. A synchronous frequency broadcasting system including a primary broadcasting station having means for generating a plurality of modulated radio frequency carrier waves having nonoverlapping sidebands, a generator of ultra high frequency oscillations, means for modulating said ultra high frequency oscillations with said modulated carrier waves, an antenna for radiating one of said carrier waves and an antenna for radiating said ultra high frequency oscillations modulated with said modulated carrier waves.

5. A system in accordance with claim 4 wherein is further provided a satellite station having an ultra high frequency receiving antenna, a detector for demodulating said ultra high frequency oscillations to derive said radio frequency carrier waves, and means for selectively radiating at least one of said carrier waves.

6. A system in accordance with claim 2 wherein is further provided a. relay station having means for receiving said higher frequency oscillations and for demodulating said higher frequency oscillations to obtain said modulated radio frequency oscillations, a source of oscillations of much higher frequency than said radio frequency and means for modulating said last mentioned higher frequency oscillations with said modulated radio frequency oscillations to provide doubly modulated higher frequency oscillations, and means for radiating said doubly modulated higher frequency oscillations,

7. A system in accordance with claim 4 wherein is further provided a satellite station having an ultra high frequency receiving antenna, a detector for demodulating said ultra high frequency oscillations to derive said carrier waves, means for selectively radiating at least one of said carrier waves, an ultra high frequency oscillator, means for modulating the ultra high frequency output of said oscillator with at least one of said carrier waves and an antenna connected to the last means for radiating the modulated ultra high frequency output of said last means.

8. A synchronous frequency broadcasting system including a primary broadcasting station having a signal source, a source of radio frequency oscillations, a modulator connected to said sources, an antenna connected to said modulator for radiating, substantially omni-directionally, modulated radio frequency oscillations derived from said modulator, a source of oscillations of a much higher frequency than said radio frequency oscillations, means for modulating said higher frequency oscillations with said modulated radio frequency oscillations, means for transmitting said higher frequency oscillations, a plurality of satellite stations each having means for receiving said higher frequency oscillations and means for demodulating said higher frequency oscillations to obtain said modulated radio frequency oscillations, said plurality of satellite stations having means for substantially omni-directionally broadcasting said modulated radio frequency oscillations in mutually overlapping radiation patterns.

9. A synchronous frequency broadcasting system including a primary broadcasting station having means for generating a plurality of modulated radio frequency carrier waves having nonoverlapping side bands, a generator of ultra high frequency oscillations, means for modulating said ultra high frequency oscillations with said modulated carrier waves, an antenna for radiating one of said carrier waves in a predetermined radiation pattern, and an antenna for radiating said ultra high frequency oscillations modulated with said modulated carrier waves, a plurality of satellite stations having each an ultra high frequency receiving antenna for receiving ultra high frequency oscillations and a detector for demodulating said ultra high frequency oscillations to derive therefrom said radio frequency carrier waves, and'means for selectively and substantlally omni-directionally radiating at least one of said carrier waves from each of said plurality of satellite stations in radiation patterns overlapping said predetermined radiation pattern.

10. A synchronous frequency broadcasting system including a primary broadcasting station having a signal source, a source of radio frequency oscillations, a modulator connected to said sources, an antenna connected to said modulator for radiating, substantially omni-direction- I ally, modulated radio frequency oscillations derived from said modulator, a source of oscillations of a much higher frequency than said radio frequency oscillations, means for modulating said higher-frequency oscillations with said modulated radio frequency oscillations, means for transmitting said higher frequency oscillations, a relay station having means for receiving said higher frequency oscillations and for demodulating said higher frequency oscillations to obtain therefrom said modulated radio frequency oscillations, a source of oscillations of much higher frequency than said radio frequency, means for modulating said last mentioned higher frequency oscillations with said modulated radio frequency oscillations to provide doubly modulated higher frequency oscillations, means for radiating said doubly modulated higher frequency oscillations, and means for radiating said last mentioned modulated radio frequency oscillations.

1 A synchronous frequency broadcasting system including a primary broadcasting station having means for generating a plurality of modulated radio frequency carrier waves having nonoverlapping side hands, a generator of ultra high frequency oscillations, means for modulatin said ultra high frequency oscillations with said modulated carrier waves, an antenna for radiating one of said carrier waves and an antenna for radiating said ultra high frequency oscillations modulated with said modulated carrier waves, a plurality of satellite stations having each an ultra high frequency receiving antenna and a detector for demodulating said ultra high frequency oscillations to derive said carrier waves and means for selectively and substantially omni-directionally radiating at least one of said -last mentioned carrier waves, an ultra high freand an antenna connected to said last named means for radiating the modulated ultra high frequency output of said last named means.

RAYMOND M. WIIMO'ITE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,397,093 Espenschied Nov. 15, 1921 1,403,841 Carson Jan. 1'7, 1922 1,447,204 Espenschied Mar. 6, 1923 1,799,978 Falknor Apr. 7, 1931 1,858,349 Terman May 17, 1932 1,987,616 Gebhard Jan. 15, 1985 2,017,128 Kroger Oct. 15, 1935 2,028,212 Heising Jan. 21, 1936 2,155,821 Goldsmith Apr. 25, 1939 2,175,270 Koch Oct. 10, 1939 2,257,917 Pungs Oct. 7, 1941 2,284,415 Goldstine May 26, 1942 2,304,969 Trevor Dec. 15, 1942 2,344,813 Goldstine Mar. 21, 1944 FOREIGN PATENTS Number Country Date 481,841 Great Britain Mar. 18, 1938 409,115 Great Britain Apr. 26, 1934

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Classifications
U.S. Classification455/20, 725/62, 455/59, 455/502, 348/723
International ClassificationH04H20/67
Cooperative ClassificationH04H20/67
European ClassificationH04H20/67