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A frequency band in which the attenuation of a filter is essentially zero.



the frequency range within which the amplitude-frequency characteristic of an acoustic, radio-engineering, or optical device is sufficiently uniform to assure the transmission of a signal without substantial distortion of the signal’s shape.

The basic parameters of a passband are the width of the band and the nonuniformity of the amplitude-frequency characteristic within the band. The bandwidth is usually defined as the difference between the upper and the lower limiting frequencies of the section of the amplitude-frequency curve where the minimum amplitude of the oscillations is not less than 0.707, or Passband, of the maximum amplitude. The nonuniformity of the amplitude-frequency curve quantitatively characterizes the degree to which the curve deviates from a straight line parallel to the frequency axis. The bandwidth is expressed in frequency units, such as hertz (Hz), and nonuniformity is expressed in relative units or in decibels.

The passband required for a particular device depends on the device’s purpose. For example, telephone systems require band-widths of 300 to 3400 Hz, high-quality reproduction of musical performances requires 30 to 16,000 Hz, and television broadcasting uses bandwidths of up to 8 MHz. The widening of a passband permits the transmission of a greater amount of information; by reducing the nonuniformity of the amplitude-frequency characteristic within the passband, the reproduction of the shape of the transmitted signal can be improved. Passbands are sometimes defined also in terms of the device’s phase-frequency characteristic.


Gonorovskii, I. S. Radiotekhnicheskie tsepi i signaly. 2nd ed. Moscow, 1971.

A. S. Grinchik

References in periodicals archive ?
h](p) are determined by optimization, to produce a dual pass band TPG characteristic under the frequency transformation (2).
Multiple layers are stacked to create sharper transitions from the pass band to the stop band regions (figure 2).
The low pass Butterworth filtration derived has the advantages of low order and higher attenuation of frequencies in pass band, improving the stability and accuracy of its response.
It can be seen that when the size is smaller, the pass band starts at higher frequency, and as the size increases, it shifts to a lower value.
The inner figure at upper-left corner shows the -3dB pass band of [BW.
Residual analysis was performed with filtered data to define differentiator filter pass band frequency and resulted in 16 Hz pass band frequency.
Any finite-bandwidth system with a fast transition from pass band to stop band cannot reproduce a square wave without encountering Gibbs-related ringing before and after the edges.
Inclusions and stress concentration are then introduced in the material and their effects on wave dispersion, attenuation and pass band are analyzed.
Optional buffered analog input provides constant input impedance across time and frequency and eliminates sample-and-hold kickback, simplifying input matching for passive and active analog front ends, while reducing pass band ripple.
The filters are characterized in terms of their frequency response, step response, impulse response, and pass band characteristics.