(redirected from passbands)
Also found in: Dictionary.


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 ?
Figures 2-5 show the spectra of the EEG signal and the filter passbands for alpha, beta, delta, and theta rhythms.
It is noted that two different feeding schemes for upper and lower passbands are used.
This gives transitional coverage between the Johnson wavelengths traditionally used in the past and the passbands many professionals use today.
5, without new shunt open stubs, there are two passbands with the center frequency of 2.
Those spurious passbands will affect the high frequency performance of the filter.
The proposed step-impedance ring resonator (SIRR) can introduce four desired passbands located at GPS (1.
It was a regular 20D with a wider passband infrared filter and other features added (S&T: November 2005, page 84).
s] = 1950 Gs, one broad passband and two narrow passbands are observed for the multi-band NRI ferrite-based metamaterials consisting of the four rods-one wire units, which is different from the transmission spectra observed for ferrite-based metamaterials consisting of rod-wire units.
The merit of above two methods is its easily tuned central frequencies (CFs) of two passbands.