This kind of a filter also called Notch Filter is a type which rejects all the frequencies which fall between two cut-off frequencies designed for it. It passes the frequencies which lie on the either sides of its.
A band-pass filter can be formed by merging one resistor capacitor low-pass filter with another RC high-pass filter. This way, a simple band-pass filter can be formed. That has a big range of frequency. A band stop filter can also be formed by combining sections of low pass and high pass filters to be able to block or reject by strongly attenuating a specific band of frequency components within the specified range of frequencies. (Tjizeed, 1195)
A Band Stop Filter, (BSF) is a frequency selector filter circuit that works in a manner that is exactly opposite to the band pass filter circuit. It is also known as the band reject filter. It allows all the signals with any frequency except the ones that lie between a specified bands known as stop bands.
If the stop band of this filter is much narrow, then the band stop filter can be called a notch filter. This would imply that the signals’ frequencies are very much attenuated over a small frequency. The frequency response will be a notch appearing to be deep and thus will have a much higher selectivity. (K.Rapahel, 1993).
For the band stop filter, it is a second order type of a filter with two poles since it has 2 cut-off frequencies, just like the band pas filter. These frequencies are commonly known as half-power points or –3dB and +3dB points (M, 1984).
Basically, the work of a band stop filter is passing all frequencies starting from zero until the first cut-off frequency point lying on the lower pint, denoted as ƒL, and pass the frequencies which fall above the second its second cut-off frequency which is on the upper limit, denoted as ƒH. It then rejects all the signals with frequencies that fall in-between. From here, it can be concluded that the bandwidth of the filter is given by BW= (ƒH – ƒL).
Typical Band Stop Filter Configuration
The addition of high pass filter and the low pass filters implies that the frequency responses of the two do not overlap, unlike for the case of the band-pass filter. This occurs is due to the fact that their starting and final frequencies lie at different frequency positions. (bandpass filter design, 2018)
The simulation was carried out in the Advanced Design Systems software and the circuit layout was as shown below
The following result shows the frequency response, obtained from the AC analysis of the circuit drawn.
The below figure shows the corresponding phase response of the circuit
ADS software enables easy and fast simulation of electronic circuits, since the band pass filter was successfully simulated and the results of the responses were obtained.
bandpass filter design. (2018, june 18). Retrieved from www.filterdesign.com
K.Rapahel. (1993). Bandpass filters. Filter Design methods and analysis, 25-33.
M, A. (1984). design of dual bandpass filter. International journal of filters, 74-95.
Tjizeed, M. (1195). Design and simulation of bandpass filter. International Journal of computer Science, 56-64.