ch14 - Chapter 14 Analog Filters 14.1 General...

Info iconThis preview shows pages 1–20. Sign up to view the full content.

View Full Document Right Arrow Icon

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

View Full DocumentRight Arrow Icon

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

View Full DocumentRight Arrow Icon

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

View Full DocumentRight Arrow Icon

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

View Full DocumentRight Arrow Icon

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

View Full DocumentRight Arrow Icon

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

View Full DocumentRight Arrow Icon

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

View Full DocumentRight Arrow Icon

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

View Full DocumentRight Arrow Icon

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

View Full DocumentRight Arrow Icon

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

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Chapter 14 Analog Filters 14.1 General Considerations 14.2 First-Order Filters 14.3 Second-Order Filters 14.4 Active Filters 14.5 Approximation of Filter Response 1 Outline of the Chapter 2 CH 14 Analog Filters Why We Need Filters In order to eliminate the unwanted interference that accompanies a signal, a filter is needed. 3 CH 14 Analog Filters Filter Characteristics Ideally, a filter needs to have a flat pass band and a sharp roll- off in its transition band. Realistically, it has a rippling pass/stop band and a transition band. 4 CH 14 Analog Filters Example: Filter I Design goal: Signal to Interference ratio of 15 dB Solution: A filter with stop band of 40 dB Given: Adjacent channel Interference is 25 dB above the signal 5 CH 14 Analog Filters Example: Filter II Given: Adjacent channel Interference is 40 dB above the signal Design goal: Signal to Interference ratio of 20 dB Solution: A filter with stop band of 60 dB at 60 Hz 6 CH 14 Analog Filters Example: Filter III A bandpass filter around 1.5 GHz is needed to reject the adjacent Cellular and PCS signals. 7 CH 14 Analog Filters Classification of Filters I 8 CH 14 Analog Filters Classification of Filters II Continuous-time Discrete-time 9 CH 14 Analog Filters Classification of Filters III Passive Active 10 CH 14 Analog Filters Summary of Filter Classifications 11 CH 14 Analog Filters Filter Transfer Function Filter a) has a transfer function with -20dB/dec roll-off Filter b) has a transfer function with -40dB/dec roll-off, better selectivity. A B 12 CH 14 Analog Filters General Transfer Function P n =n’th pole Z m =m’th zero ( 29 ( 29 ( 29 ( 29 ( 29 ( 29 1 2 1 2 ( ) m m s Z s Z s Z H s s P s P s P α--- =--- L L 13 CH 14 Analog Filters Pole-Zero Diagram 14 CH 14 Analog Filters Position of the Poles Poles on the RHP Unstable (no good) Poles on the jω axis Oscillatory (no good) Poles on the LHP Decaying (good) 15 CH 14 Analog Filters Imaginary Zero Imaginary zero is used to create a null at certain frequency. 16 CH 14 Analog Filters Sensitivity P C dP dC S P C = Sensitivity measures the variation of a filter parameter due to variation of a filter component. P=Parameter C=Component 17 CH 14 Analog Filters Example: Sensitivity ( 29 1 1 / 1 1 1 1 1 2 1 1 1 1- =- =- = = ϖ ϖ ϖ ϖ ϖ R S R dR d C R dR d C R 18 CH 14 Analog Filters First-Order Filters 1 1 ( ) s z H s s p α + = + First-order filters are represented by the transfer function shown above....
View Full Document

This note was uploaded on 04/05/2010 for the course EE EE taught by Professor Ee during the Spring '10 term at Korea Advanced Institute of Science and Technology.

Page1 / 66

ch14 - Chapter 14 Analog Filters 14.1 General...

This preview shows document pages 1 - 20. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online