Band Stop

Filter circuit symbol.

Filter configuration window.

Defines a band stop filter with the parameters shown in the configuration window above. A band stop filter passes frequencies in the pass bands with minimal attenuation and rejects (attenuates) signals outside of the pass bands. A band stop filter will pass both low and high frequencies and attenuate a specific band of frequencies as seen below in the plot of a band pass filter in EMIT. A band stop filter can be thought of as a low pass filter and a high pass filter cascaded together with a portion of their stop bands overlapping. In essence, a band stop filter has two pass bands. A band stop filter is sometimes referred to as a notch filter.

Noise Temperature (K): Noise power added by the filter.

Insertion Loss: Insertion loss defines the magnitude by which pass band signals are attenuated and is specified in dB. The pass bands of the band stop filter are defined as all frequencies that are below the lower cutoff frequency and above the higher cutoff frequency.

Stop Band Attenuation: Stop band attenuation defines the magnitude of the attenuation for signals with frequencies above the lower stop band frequency and below the higher stop band frequency. The attenuation of signals with frequencies between the lower cutoff frequency and the lower stop band frequency or between the higher stop band frequency and the higher cutoff frequency is determined by calculating the slope between these points and assuming a linear roll-off.

Lower Cutoff: The lower cutoff defines the maximum frequency of the lower pass band. All frequencies between DC and the lower cutoff frequency are attenuated by an amount equal to the filter's insertion loss.

Lower Stop Band: The lower stop band defines the minimum frequency of the stop band. All frequencies between the lower stop band value and the higher stop band value are attenuated by an amount equal to the stop band attenuation.

Higher Stop Band: The higher stop band defines the maximum frequency of the stop band. All frequencies between the lower stop band value and the higher stop band value are attenuated by an amount equal to the stop band attenuation.

Higher Cutoff: The higher cutoff defines the minimum frequency of the higher pass band. All frequencies above the higher cutoff are attenuated by an amount equal to the filter's insertion loss.