| Autor: |
R. W. Beckwith |
| Rok vydání: |
1952 |
| Předmět: |
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| Zdroj: |
Transactions of the American Institute of Electrical Engineers. Part III: Power Apparatus and Systems. 71:1085-1088 |
| ISSN: |
0097-2460 |
| DOI: |
10.1109/aieepas.1952.4498579 |
| Popis: |
Itwouldbepossible touseafilter ofthe proper bandwidth intheoutput ofeach transmitter toafford thedesired isolation;however, wherethechannels are spaced only1/2percentinfrequency, as arecrystal-controlled frequency-shift controlchannels, these filters becomevery expensive andhaveahighinsertion loss whichwoulduseupalarge portion ofthe useful operating rangeofthechannel equipment. Radio-frequency (r-f) hybrid units have beendesigned asamoreeconomical, less bulkysolution tothisproblem.The principal ofoperation issimilar tothatof themorefamiliar audiohybrids4 which areusedtoform4-wire to2-wire audio connections. Inthislater casevarious bridge orbalance circuits havebeenused topermit tying a2-wire telephone line to anincoming andoutgoing amplifier withoutcoupling theamplifiers together and causing singing. Asimilar balance circuit applied tocarrier-current linecoupling permits coupling twocircuits tothepower line withaminimumofcoupling between thetwocircuits. Whentransmitters are coupled totheline through anetwork of these hybrid units apowerloss ofabout l/nresults (nagainisthenumberof transmitters). Thismeanstheloss indecibels duetocoupling ofntransmitters is onlyhalf that imposed bystraight parallel operation. Hybrid-A Multiterminal Network Theideal circuit solution tothis problemwouldbeacomplex hybrid withmany pairs ofinputterminals' andonlyone balance andoneloadpair. Suchanideal network wouldhaveonlya3-decibel loss perchannel because oftheequal division ofenergy between theloadandbalance. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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