Lecture18

# Probe elements added to inject signals to measure the

This preview shows pages 4–7. Sign up to view the full content.

Probe elements added to inject signals to measure the open loop response from the closed loop system This example is based on posts contributed by Frank Wiedmann to the independent users' group at --- C:\Program Files\LTC\SwCADIII\examples\Educational\LoopGain2.asc ---

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
10/7/09 3 Finding A ! : Abstract View ! " ! \$ ! % & & ( & ) & * & \$ & ( + & ) ,- + & . & ) & ) /" 0 ",-1 + & & ) + & ,/" 0 ",-1 2* )*3 - 8 999 8%\$7 Finding A ! : Abstract View ! " ! \$ ! % & & ( 6 7 & ) 6 & & * & \$ !’’:;< & =*3> ?*:3 @A? A3*:BC DE< F(3F:(D (B DE< C(3<FG*B *HH*’(D< )3*; DE< )<<CIAF> ’(JBAK L*@M N<3<5 ’(JBAK L*@ (’ FK*F>@(’<5 ’* @< ABAK?O< @*3>(BJ F*:BD<3FK*F>@(’<M P 999 8%\$7
10/7/09 5 Finding A ! : Abstract View ! " ! \$ ! % & & \$ & ( ) & & ( ) ! % & * + ’* & * ) & ( ,! % & * ,& ( ) & * ,& ) ",! % -* ./0 12*’0342**5 6789 7’’:;896 < ! = 8’ & 8 > ? & ( > & & * > & ( ,! % @ AAA B%\$? Finding A ! : Abstract View ! " ! \$ ! % & & \$ & ( ) & & ( ) ! % & * + ’* & * ) & ( ,! % & * ,& ( ) & * ,& ) ",! % -* ./0 12*’0342**5 6789 7’’:;896 < ! = 8’ & 8 > ? & ( > & & * > & ( ,! % "? AAA B%\$? Feedback has the interesting property of letting us swap “cause” and “effect”. It’s easiest to understand using math. The relationship we want is xo = xs*(1/A3). To make it happen we put the inverse relationship xf = xs = A3*vo in the feedback loop. Here, the input xs is expressed as an “effect” of the output, xo. The feedback lets us” divide through” to get vo as a function of the input. The feedback solves the equations for us to find the value of xi required to make xo = xs*(1/A3).

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
10/7/09 6 Finding A ! : Abstract View ! " ! \$ ! % & & ( & ) & * + & ) ,! \$ ! % + & ,! \$ ! % -) ./ 012 30*’/4 50/ *65765 1’ 50/ (4765 5* ! \$ 8 ./92 01:/ 012 5* .*;< )6;50/; ==> 1;*642 50/ ?**[email protected] A0/4 50/ 4/. 3?*’/2B?**7 C1(4 1’’6D(4C A ! E .*6?2 F/ A ! + ",! \$ ! % "" GGG H%\$I Finding A ! : Abstract View ! " ! \$ ! % & & ( & ) & * + & ) ,! \$ ! % + & ,! \$ ! % Usually we try to put something in the output-back-to-input feedback path whose inverse is a function we want. As we will see, this is a very powerful concept that extends way beyond linear circuit analysis. "\$ GGG H%\$I
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern