High pass filter with analog electronic

A high-pass filter is a filter that passes high frequencies well, but attenuates (or reduces) frequencies lower than the cutoff frequency.

1. Welcome to our presentation 1 Topic: High-pass filter By Dilouar Hossain Email- [email protected]

2. Group members : 1. Md. Saiful Islam- 151-33-2411 2. Shreekanta Sarker- 151-33-2469 3. S.M. Sabbir Hossain- 151-33-2322 4. Majbah Uddin Ahmed- 151-33-2505 5. Rajib Laskar- 151-33-2349 2

3. High-pass filter A high-pass filter is a filter that passes high frequencies well, but attenuates (or reduces) frequencies lower than the cutoff frequency. The actual amount of attenuation for each frequency varies from filter to filter. A high-pass filter is the opposite of a low-pass filter. It is useful as a filter to block any unwanted low frequency components of a complex signal while passing the higher frequencies. 3

4. High Pass Filter a) 1 st Order A V (dB) A V(max) A V(max) - 3 f c 0.1f c 0.01f c A V(max) - 20 A V(max) - 40 +20dB/ dec f (Hz) R 1 R 2 _ + V in +V -V R A C A V o

5. Analysis At 0 < f < f c , high pass filter will attenuate the frequencies at roll-off of +20dB/decade because X CA is decreasing starts from ∞. When X CA =∞, 5 At f = f c , the gain is 0.707A V(max) or in dB, A VdB (max) -3 where the magnitude of the capacitive reactance, X CA equals the resistance of the resistor, R A At f > f c , high pass filter will pass the frequencies because X CA is decreasing to 0  . When X CA =

6. 40dB/decade filter Design procedure : 1.choose a cutoff frequency. 2. Let c1=c2=c and choose a convenient value. 3. R1 = 1.414/ WcC 4. R1 = 2R2. 5. Rf = R1

7. 7 V o R 1 R 2 _ + V in +V -V R A C A C B R B A V (dB) A V(max) A V(max) - 3 f c 0.1f c 0.01f c A V(max) - 40 A V(max) - 80 +40dB/dec f (Hz) A V(max) = 1+ R 1 R 2 1 2  R A R B C A C B f c = f A f B 1 2 R A C A 1 2 R B C B  = =

8. +60dB/decade filter: 8 A high-pass filter of +60 db/decade can be constructed by cascading a +40 db/decade filter with a +20 db/decade filter.

9. Design procedure of +60 db/decade high pass filter: 1. choose cutoff frequency Wc or fc. 2.Let C1=C2=C3=C and choose a convenient value between 100 pF to .1 mF 3. R3= 1/ WcC 4. R1=2R3 5. R2= R3/2 9

10. Applications of active high pass filters -These are used in the loud speakers to reduce the low level noise. -Eliminates rumble distortions in audio applications so these are also called are treble boost filters. -These are used in audio amplifiers to amplify the higher frequency signals. -These are also used in equaliser . 10

11. Thank you…. 11