악성 광고 게시물 대책이 강구될 때까지 일시 중단합니다
1998/09/23 (18:40) from 203.127.155.65' of sngrel1a.hp.com.sg' Article Number : 17
Delete Modify Anonymous (dong-won_lee@hp.com) Access : 7260 , Lines : 88
Re: 질문 있습니다! - 공진과 임피던스 매칭.
恩 wrote:
>공진과 임피던스 매칭이 자꾸 혼동 되는데...
>아시는 분은 아시는데로 가르쳐 줬으면 고맙겠습니다.
>
>참고로 'RF Globalnet' 사이트가 아주 좋은 거 같습니다.
>저도 자주 들러 보는데,,,,,,,
>시간이 나신다면 꼭 들러보세요..
>인터넷 주소는 "<http://www.rfglobalnet.com>"입니다.


Sorry for the English.
Let me tell you what I can

I. Resonance

You can see the device characters with frequency as below

Re|  *                  
ac|    *                      Capacitor
ta|      *               *
nc|        *          *
e |         *       *
 |          *    *
 |           * *
 ----------------------------
              fr


 |             *                    Inductor
 |           *   *
 |         *       *
 |      *            *
 |    *                *
 | *                      *
 -----------------------------------------
              fr

If you combine two together, you will notice Resonance Phenomenia at fr with maximum current and minimum Impedance. C and L will be selected for
the right Bandwith or freq. (need to consider Q factor)


II. Impedence Matching
When a impedence is selected, you need to provide the maximum possible transfer of power between a source and it's load.

Case1) DC
Let's say we have this circuit.

     ----- Rs ---------------- VLoad
     |             |
     |            RLoad
  Vsource          |
     |             |
     =             =

Pout will be the maximum at Rs/Rl=1 (why, Pload=Vload^2/RLoad -> RLoad*Vsource/(Rs+RLoad) )

ex1)Rs=100, Vs=1V, RLoad=100 when matching
PLoad=0.0025 Watt

ex2)Rs=100, Vs=1V, RLoad=1000
PLoad=0.0008265 Watt

Therefore -4.8dB down (2/3 Power Loss)


Case2) AC
Same as DC, but you need to erase conjugate impedence.

---- Rs ---- +jX --- ? ----
                         |
                         Rload

In this case, you need to apply -jX (as capacitor to eliminate Reactive one)


Therefore Resonance will be used for  selective power transmission and Impedance matching is for maximum power transmission. But you have to use
two methods together corresponding to your design

For example, Impedance Mathcing with DC block (DC can not flow into it),
Bandpass, StopBand. In other words, think the bandwith first and match your circuit.

I hope you like it.
P.S I'm very lousy at Korean Key Board.




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