lec14-handout-6up

lec14-handout-6up - 6.003 Signals and Systems Lecture 14...

Info icon This preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
6.003: Signals and Systems Lecture 14 October 29, 2009 1 6.003: Signals and Systems CT Feedback and Control October 29, 2009 Feedback and Control Continuous-time feedback has many applications. Examples: improve performance of an op amp circuit. control position of a motor. reduce sensitivity to unwanted parameter variation. reduce distortions. stabilize unstable systems magnetic levitation inverted pendulum Feedback and Control Reducing sensitivity to unwanted parameter variation. Example: power amplifier F 0 MP3 player power amplifier 8 < F 0 < 12 speaker Changes in F 0 (due to changes in temperature, for example) lead to undesired changes in sound level. Feedback and Control Feedback can be used to compensate for parameter variation. F 0 MP3 player K β + power amplifier 8 < F 0 < 12 speaker X Y H ( s ) = KF 0 1 + βKF 0 If K is made large, so that βKF 0 1 , then H ( s ) 1 β independent of K or F 0 ! Feedback and Control Feedback reduces the change in gain due to change in F 0 . F 0 MP3 player 100 1 10 + 8 < F 0 < 12 X Y 0 10 20 0 10 20 8 < F 0 < 12 F 0 Gain to Speaker F 0 (no feedback) 100 F 0 1 + 100 F 0 10 (feedback) Check Yourself F 0 MP3 player K β + power amplifier 8 < F 0 < 12 speaker X Y Feedback greatly reduces sensitivity to variations in K or F 0 . lim K →∞ H ( s ) = KF 0 1 + βKF 0 1 β What about variations in β ? Aren’t those important?
Image of page 1

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

View Full Document Right Arrow Icon
6.003: Signals and Systems Lecture 14 October 29, 2009 2 Crossover Distortion Feedback can compensate for parameter variation even when the variation occurs rapidly.
Image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    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.

    Student Picture

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

  • Left Quote Icon

    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.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    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.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern