Passband

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passband

[′pas‚band]
(electronics)
A frequency band in which the attenuation of a filter is essentially zero.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

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

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
As can be noticed in Figure 5(b), (19) corresponds to a pass-band filter with unit amplitude and central frequency at [[omega].sub.0].
The pass-band ripple characteristic of LP response is preserved through the transformation process.
On the other hand, a good band-pass filter requires high transmission in the pass-band and high attenuation in the stop band.
It is observed that this filter gives us a large bandwidth and also the group-delay of this band-pass filter is linear in its pass-band (see Figure 26).
which means that the pass-band and stop-band edges ([[omega].sub.c] & [[omega].sub.s], respectively) are related by [[omega].sub.c]T + [[omega].sub.s]T = [pi].
Then an common phenomenon in ([M.sub.1], [M.sub.2]), ([M.sub.3], [M.sub.4]) is discovered: on the condition that incident angle [theta] remains unchanged, if [phi] increases, the resonant frequencies will increase as well; meanwhile, the loss will decrease, and pass-band will remain unchanged.
Zeng, "Complementary split ring resonators with dual mesh-shaped couplings and defected ground structures for wide pass-band and stop-band BPF design," Progress In Electromagnetics Research Letters, Vol.
The width of the pass-band (between [f.sub.0] and [f.sub.1]) diminishes with the increase of the dielectric constant, making the filter more selective.
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