GB2188214A

GB2188214A - Method and device for combining RF transmitters

Info

Publication number: GB2188214A
Application number: GB08625869A
Authority: GB
Inventors: Jose Eduardo Januario De Souza; Luiz Rutman Goldsztejn
Original assignee: RUTMAN GOLDSZETJN LUIZ
Current assignee: RUTMAN GOLDSZETJN LUIZ
Priority date: 1986-03-19
Filing date: 1986-10-29
Publication date: 1987-09-23
Also published as: SE8601866L; BR8601220A; IT1191822B; JPS62221224A; DE3615355A1; FR2596225A1; GB2188214B; IT8620949A0; DE3615355C2; SE8601866D0; IT8620949A1; GB8625869D0

Abstract

The outputs 31-3n+1 from a plurality of RF transmitters 41-n+1 are fed via cyclically operated switches 9 to a common output 5, the resulting signal, after amplification and filtering, being fed to antenna 8. <IMAGE>

Description

SPECIFICATION Method and device for combining RFtransmitters This invention relates to a method and device for combining RFtransmitters.

An object is to provide a method and device for combining various RFtransmitters, applicable in the transmission of radio frequencies, for example, in a radiotelephony transmission system, in orderto improve efficiency as compared to conventional methods and devices, as well as to simplify the device relative to conventional ones.

In certain types ofequipmentand/or circumstances of use or of certain types of equipment, such as,forexample,equipmentthat operates a radiotelephonytransmission system, there is a need to combine various RF transmitters, to be radiated by a single antenna.

To meetthis need, a power-additive or antenna-combining filter is used, interposed between the RF transmitter output and the antenna input and in which each pair of RFtransmitters ofthe setof RFtransmitters to be combined is combined by a corresponding RF hybrid and each pair of resulting RF hybrids, in turn, is likewise combined, which combinations proceed until a single RF output is obtained, which is then coupled to the antenna input.

In spite of the wide use of this method and device, it is liableto some criticism, because of low efficiency due to the large loss of power that occurs in each RF hybrid, where the effective output power corresponds to half the input power.

Anotherdisadvantageto be noted in the conventional combiner device has to do with the large physical volume that it may reach, since it can be provided with numerous RF hybrids, power-dissipation loads, cable form, and the like, which likewise help to make the equipment more complex, notonlyfromthestandpointof construction, but also for maintenance operations.

Added to these disadvantages of a technical nature, the problems of an economic nature should also be stressed, since the low efficiency ofthe conventional device and methods result, consequently, in higher power consumption, which makes operation ofthe equipment more expensive.

On the other hand, complexity ofthe equipment and difficulty in maintenance, as may be expected, also represent an additional outlay.

According to one aspect ofthe present invention, there is provided a method for combining RF transmitters, comprising a combining stage of signals coming from RF transmitters to be combined, amplification ofthe combined signals, filtering of the combined signals, and radiation ofthe combined signals, wherein the actual combining stage is accomplished by sequential, continuous and cyclic keying oftheRFchannel outputsto be combined.

According to a second aspect ofthe present invention, there is provided a device for combining RFtransmitters, the device including an antenna combiner comprising a combining device with inputs corresponding to the RFtransmitters to be combined, each receiving signals from a respective RFchannel and a single common outputforthe already combined RF cha n nels, this to a filter and this, in turn, to the antenna, wherein the combining device comprises a keying device which is made up of a plurality of keys, each corresponding to a respective RF channel of a set of RF channels to be combined, all of which are interconnected to a single common output and controlled by an oscillator, with said filter being of a band-pass type.

For a better understanding ofthe invention, and to show how the same may be carried into effect, reference will now be made, bywayofexample,to the accompanying drawing, in which the single Figure is a block diagram ofanapparatusfor accomplishing the combination of RFtransmitters.

The present method for combining RFtransmitters includesthestagesof: a) combiningsignalsfromthevariousRF transmitters to have their signals combined; b) amplification of the combined signals; c) filtering of said combined signals; and d) radiation of said combined signals.

The combination ofthe signals sent by the RF channels, instead of being done by a RF hybrid, as conventionally, is accomplished by sequential, continuous and cyclic keying (connection and disconnection) of the outputs ofthe RF channels to be combined.

The device illustrated that implements this method includes an antenna combiner 1 made up of a combining device 2, which accomplishes the actual combining stage, provided with a plurality of inlets 31; 32; 3n+1x each corresponding to a respective RF channel 4, of a setof RFchannels41;42 4n+1 to be combined, and a receiver S of the corresponding signals Si S2 Sn+1 of same. The receiver S represents inlets ofthe device 2, viz. the inletS1 receives RFsignalsfrom the channel 41 via inlet S1, S2 receives signals from 42 via inlet 32 and soon.The combining device 2 is provided with a single outlet 5, common to the combined signals S1 sS2 Sn+1 of the RF channels 41;42....4142.....4n+1 to be combined and connected to the input of an amplifier 6, which provides the amplification stage of the signals combined S1;S2.....Sn+1 and connected to the input of a filter7, which eliminates undesirable frequencies arising from the combination, and whose output is connected to the input of an antenna 8, which accomplishes radiation of the combined signalsS1;S2 Sn+i.

The combining device 2 includes a keying device provided with a plurality of keys 9, each corresponding to a respective RF channel 41;42.....4n+1 to be combined, connected at one side to a corresponding input 3, and at the other to the common output 5, all of which being controlled by an oscillator 10.

In this manner, each RF channel 41;42.....4n+1 to be combined is connected to the output 5 by its corresponding key 9, immediately afterthe disconnection ofthe immediately preceding RF channel 41 or42 or 4n+1, which connected channel remains in the connected state for an extremely short interval oftime, during which it sends its signal S1 or S2 or Sun+1, afterwhich it is disconnected by opening the aforementioned respective key9 and following which the RF channel 41 or42 or .....4n+1 immediately succeeding is connected by closing the corresponding key 9, which operation is performed continuously and cyclically, that is, afterthefirst RF channel 41 or42or 4n+1 ofthe sequence of channels accomplishesthis,the remaining RF channels ofthe sequence accomplish it one after another uptothe last RFchannel, afterwhich thefirst RFchannel again accomplishes this and a new cycle begins, which enables the signals S1 or S2 or 5n+1 of a given RF channel 41 or42 s 4n+1 to be interposed between the RF channel signals immediately preceding or succeeding it. The signals arriving atthe common outlet 5 thus are amplified individually in the amplifier 6 and then fed tothe filter 7. The oscillator 10 determines the length ofthe pulses by controlling the times of closure of the respective keys 9 and the rate at which they are sequentially switched.

Thefilter7 is of a band-passtype and actstowards removing the strips arising from the keying operation.

With the described method and equipmentfor combining RFtransmitters, manyofthe disadvantages of the conventional ones are overcome, since these provide much greater efficiency and the equipment is of a smaller size and of a moresimpleconstruction.

Claims

1. Amethodforcombining RFtransmitters, comprising a combining stage of signals coming from RFtransmittersto be combined, amplification of the combined signals, filtering ofthe combined signals, and radiation ofthe combined signals, wherein the actual combining stage is accomplished by sequential, continuous and cyclic keying ofthe RF channel outputs two be combined.

2. A method for combining RFtransmitters, substantially as herein before described with reference to the accompanying drawings.

3. Adeviceforcombining RFtransmitters,the device including an antenna combiner comprising a combining device with inputs corresponding to the RFtransmittersto be combined, each receiving signals from a respective RF channel and a single common outputforthe already combined RF channels, this to filter and this, in turn, to the antenna, wherein the combining device comprises a keying device which is made up of a plurality of keys, each corresponding to a respective RF channel of a set of RF channels to be combined, all of which are interconnected to a single common output and controlled by an oscillator, with said filter being of a band-pass type.

4. Adeviceforcombining RFtransmitters, substantially as herein before described with referenceto the accompanying drawing.