Passband


Also found in: Dictionary, Wikipedia.

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 ?
UWB passband is realized using a tight coupling between the MMR and input/output 50 [ohm] transmission lines.
Thus, the passband selectivity and stopband rejection of the filter can be effectively improved.
By attaching the two dissimilar short-circuited stubs to the uniform-impedance ring resonator (UI-RR), the three resonant modes are appropriately excited to form up a wide passband.
Provides Additional Flat Attenuation Within A Passband Of 5-870 Mhz.
The first method is to utilized two sets of resonators, one operates at the upper passband and the other at the lower passband [14].
There are many methods to design multi-band filters, such as combining two single-band filters at different passband frequencies [1-5], adding defected stepped impedance resonator (DSIR) and microstrip stepped impedance resonator (MSIR) [6-9] or adding a couple of resonators [10-13].
In the passband, the characteristic impedance is real, while it becomes imaginary in the stopband when the modified CRLH unit cell is operating in the unbalanced case, and it is matched to the port impedance [R.
Two types of low-order elliptic filters are used several times in order to implement a higher order filter with the same passband and stopband edge frequencies, in such a way that overall filter has a very small passband ripple and may have very large stopband attenuation.
The frequency at which the response changes from passband to stopband is referred to as the cutoff frequency.
This series uses a 7-section high pass filter design and provides good passband matching (typical VSWR is 1.