Active Filters.pdf
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The document provides an overview of active filters, which are analog circuits that utilize active components like amplifiers to implement frequency selective filtering. It classifies active filters into four types: low pass, high pass, band pass, and band stop, detailing their functions, configurations, and frequency responses. The document also discusses the merits and demerits of active filters, including their flexibility and performance benefits, while highlighting their limitations in cost, power handling, and frequency range.
Active Filters.pdf
- 1. Presented By: Group 3 Ipsita Raha – Dibyendu Banik – Arijit Dhali 11500120054 – 11500320062 – 11500320078 Active Filters
- 2. Table of contents 02 01 04 Overview of Active Filter & its Types Introduction Configuration & Merits – Demirits 03 Conclusion & References
- 3. Introduction An active filter is a type of analog circuit implementing an electronic filter using active components, typically an amplifier. Amplifiers included in a filter design can be used to improve the cost, performance and predictability of a filter.
- 4. What is a Filter? A filter is basically a “ frequency selective “ circuit. It is designed to pass a specific band of frequencies and block input signals of frequencies outside this band. Classification of Filters:
- 5. Active filters are the electronic circuits, which consist of active element like op-amp(s) along with passive elements like resistor(s) and capacitor(s). Active filters are mainly classified into the following 4 types based on the band of frequencies that they are allowing and / or rejecting − ● Active Low Pass Filter ● Active High Pass Filter ● Active Band Pass Filter ● Active Band Stop Filter What is Active Filter?
- 6. Active Low Pass Filter This filter designed to pass all frequencies below a given cut-off frequency Cut-off Frequency : Fc = 1 2𝜋𝑅𝐶 Phase Shift : 𝜑 = −45°
- 7. o It shows that a low pass filter has a constant gain from 0 to a high cut off frequency fc. o The frequencies between 0 to fc are known as “ passband frequencies” whereas the frequencies beyond fc are known as the “stopband frequencies”. o At f= fc the filter gain makes a sudden transition to zero. Therefore all the frequencies beyond fc are completely attenuated. o This figure shows the frequency response of a practical low-pass filter. gain does not change suddenly at f= fc. Instead as f increase, the gain reduces gradually. Configuration of Active Low Pass Filter Frequency Response of Low Pass Filter
- 8. Active High Pass Filter This filter designed to pass all frequencies above a given cut-off frequency. Cut-off Frequency : Fc = 1 2𝜋𝑅𝐶 Phase Shift : 𝜑 = +45°
- 9. o Its “stopband” extends from f=0 to f=fc where fc is the cut off frequency. the “passband” will be for all frequencies above Fc. o The gain of an ideal high-pass filter is 0 over its stopband constant over its passband. o The gain make a sudden transition from 0 to 1 at f= fc Configuration of Active High Pass Filter Frequency Response of High Pass Filter
- 10. Active Band Pass Filter This filter is designed to pass all frequencies that fall between its cut-off frequencies(FC1 and FC2) Center Frequency : Fr = 𝐹𝐿 ∗ 𝐹𝐻 Phase Shift : 𝜑 = 180°
- 11. o Its “passband” extends between the two cut-off frequencies fL anfd fH with fH>fL. The frequencies outside this passband lie in the “stopband “. o The gain of an ideal bandpass filter is 0 over the stopband and constant over its passband. o The gain will make sudden trasitions from 0 to 1 at f=fL and from 1 to 0 f=fJ Configuration of Active Band Pass Filter Frequency Response of Band Pass Filter
- 12. Active Band Stop Filter This filter in designed to block all frequencies that fall between its cut-off frequencies(FC1 and FC2) Center Frequency : Fc = 𝐹𝐿 ∗ 𝐹𝐻 Phase Shift : 𝜑 = 180°
- 13. o The transformation of this filter characteristic can be easily implemented using a single low pass and high pass filter circuits isolated from each other by non- inverting voltage follower, (Av = 1). o The output from these two filter circuits is then summed using a third operational amplifier connected as a voltage summer (adder) Configuration of Active Band Stop Filter Frequency Response of Band Stop Filter
- 14. Merits & Demerits Merits o Flexibility in gain o No loading problem o No insertion o Passband gain o Small component size o Use of the inductors can be avoided o Control impedance Demerits o Costs more than Passive Filter o Its has need dc supply. o Active filter are limited in their frequency range .op-amp had a finite gain bandwidth product. o Active filters can not handle of large amount of power.
- 15. Active filters are used in communication systems for suppressing noise, to isolate a communication of signal from various channels to improve the unique message signal from a modulated signal. These filters are used in instrumentation systems by the designers to choose a required frequency apparatus and detach unwanted ones. These filters can be used to limit the analog signal’s bandwidth before altering them to digital signals. Conclusion
- 16. • https://www.tutorialspoint.com/linear_integrated_circuits_applications/linear_integrated_circuits_applica tions_active_filters.htm • https://www.slideshare.net/Bangulkhanbaloch/active-filter-138582261 • https://www.slideshare.net/RajputManthan/active-filter • https://www.electronics-tutorials.ws/filter/band-stop-filter.html • https://www.electronics-tutorials.ws/filter/filter_6.html • https://www.electronics-tutorials.ws/filter/filter_7.html • https://www.electronics-tutorials.ws/filter/filter_5.html Reference
- 17. For your precious attention towards our presentation Thank You