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Multiple feedback bandpass filter Description

2015-01-18 18:16  
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Next, a plurality of band pass filters introduce feedback. Please take a few seconds to browse to the following schematic. Source impedance must be low on the input resistance, and these filters are usually driven from an opamp buffer. If a high impedance is used, it increases the total input resistance, lead to unpredictable center frequency and response. opamp shows a single device, but most often double or four opamps be used in such applications. A resistor from the ve input of opamp is optional. If used, the resistance value should be the same as R3 to obtain a minimum DC offset opamp output. 100 years nf capacitor is highly recommended to bypass the non-inverting input of the Earth's communication helps reduce noise. If your problem is not an offset, but the non-inverting input connected to the earth (ground) rail as shown. C4, C5 are supply bypass  capacitors  should be used at each IC program. Ceramic capacitors are recommended most effective high frequency bypassing. The opamp can be any common device for the lower frequencies, but at high frequencies (above figure 2 kHz) high-speed units in order to obtain the best performance requirements.


Figure 1 – Multiple Feedback Bandpass Flter