Passband


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passband

[′pas‚band]
(electronics)
A frequency band in which the attenuation of a filter is essentially zero.

Passband

 

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.

REFERENCE

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

A. S. Grinchik

References in periodicals archive ?
where M is the up-sampling rate for Ha(z), fp and fs are the passband and stopband edges of the overall filter, fap and fas are the passband and stopband edges of the modal filter Ha(z), fmap and fmcp are the passband edges and fmas and fmcs are the stopband edges of the two masking filters respectively.
11) Whilst each telescope is capable of taking images using the Johnson/ Bessell BVRI passbands as well as unfiltered images, only unfiltered images could be requested of M101 through the OWN web portal.
To provide a guideline for designing the optical filter's characteristics, we devise an optimal characteristic of the optical filter in the sense that, with a fixed passband of the optical filter, the second moment of the square of the interferogram is minimized.
In many applications K is a finite union of disjoint intervals or complex arcs (the frequency bands), and both g and w are piecewise constant functions (the values 0 and 1 of g corresponding to the so-called stopband and passband, respectively).
If uniform frequency bands used, means all the passband ranges of equal size of all channels of filter bank, distortion occurs at the output image.
1 dB passband ripple, 60 dB stopband attenuation, [+ or -] 10% width of the cutoff band and 2.
It is designed to have a frequency response that is as flat as mathematically possible in the passband.
Again, these measurements are with the grill in place, resulting in the response ripples seen in the tweeter passband.
The passband is up to 2500 MHz with a passband ripple of .
The creation of complete absolute spectra readily provides calibrators for ANY well-characterised passband lying entirely in the range 1.
diameter Type 27 wheels (from a number of manufacturers) were tested using Third Octave Band vibration analysis with filters that have upper and lower passband limit ratios of 2.
The AQ and BQ filters deliver high channel isolation and wide passband performance, as well as ultralow dispersion characteristics.