Download Band Stop Filter using Operational Amplifier and more Study Guides, Projects, Research Electronics in PDF only on Docsity!
BAND STOP FILTER BY
USING OP-AMP
BRIEF DESCRIPTION
A band Stop Filter known also as a Notch Filter, blocks and rejects frequencies that lie between its two cut-off frequency points passes all those frequencies either side of this range. Typically, the width of the stopband is 1 to 2 decades (that is, the highest frequency attenuated is 10 to 100 times the lowest frequency attenuated). However, in the audio band, a notch filter has high and low frequencies that may be only semitones apart.
BLOCK DIAGRAM
INTRODUCTION OF
INSTRUMENTS
1. Low pass filter:
A low-pass filter (LPF) is a filter that passes signals with a frequency lower than a certain cutoff frequency and attenuates signals with frequencies higher than the cutoff frequency.
before. The band stop filter, also known as a band reject filter, passes all frequencies with the exception of those within a specified stop band which are greatly attenuated. If this stop band is very narrow and highly attenuated over a few hertz, then the band stop filter is more commonly referred to as a notch filter, as its frequency response shows that of a deep notch with high selectivity (a steep-side curve) rather than a flattened wider band. Also, just like the band pass filter, the band stop (band reject or notch) filter is a second-order (two-pole) filter having two cut-off frequencies, commonly known as the - 3dB or half-power points producing a wide stop band bandwidth between these two - 3dB points. Then the function of a band stop filter is too pass all those frequencies from zero (DC) up to its first (lower) cut-off frequency point ƒL, and pass all those frequencies above its second (upper) cut-off frequency ƒH, but block or reject all those frequencies in-between. Then the filters bandwidth, BW is defined as: (ƒH – ƒL). So for a wide-band band stop filter, the filters actual stop band lies between its lower and upper - 3dB points as it attenuates, or rejects any frequency between these two cut-off frequencies
Band Stop Filter Response:
phase shift:
We can see from the amplitude and phase curves above for the band
pass circuit, that the quantities ƒL, ƒH and ƒC are the same as those
used to describe the behaviour of the band-pass filter. This is because
the band stop filter is simply an inverted or complimented form of the
standard band-pass filter.
Simulation:
Trouble shooting:
In simulation the terminals of operational amplifier were miss attached due to which the responses were not showing. The negative was attached to ground.
amplifier and makes the best equipment. These are also used in some of the acoustic applications like mandolin, base instrument amplifiers. In communication electronics the signal is distorted due to some noise (harmonics) which makes the original signal to interfere with other signals which lead to errors in the output. Thus, these filters are used to eliminate these unwanted harmonics. These are used to reduce the static on radio, which are commonly used in our daily life. These are also used in Optical communication technologies, at the end of the optical fiber there may be some interfering (spurious) frequencies of light which makes the distortions in the light beam. These distortions are eliminated by band stop filters. The best example is in Raman spectroscopy. In image and signal processing these filters are highly preferred to reject noise. These are used in high quality audio applications like PA systems (Public address systems). These are also used in medical field applications, i.e., in biomedical instruments like EGC for removing line noise.
